Bought this game a few days ago, questions

[Kwoon]

Most of these have been answered but I'll give it a go again just in case:
The jobs are acquired after completing the base classes quests (up to level 30) and an additional class to level 15. It differs for each one but MOST of them make sense. Don't be afraid to play around with each of them though. Once you get deeper into the game cross class abilities become the major point of customization for your character so having those classes leveled (and those skills already unlocked) is extremely useful. Like you said, its a one time thing.

Dark Knight and Astrologian are special. They're jobs with no base classes, they start at level 30. However you need access to HW content before you can use them which (and I hate having to say this) means you need to complete the story of A Realm Reborn to access. It'l take a little while, but its worth it since the classes/jobs you level on the way will likely have some cross class abilities you needed anyway.
Crafting is still useful even if most people tell you it isn't. End game gear isn't made from crafting though, that all comes from Dungeons/Raids and Tomestone collecting. However, having a crafter class leveled means you can repair your gear even in an instance (extremely important because you'll never live that ONE time you forgot to repair before going in down) and you can make High Quality gear for any new classes you decide to level which makes it THAT much easier to progress. They also make some nice cosmetic items for your glamours or house/private room and you'll also need them leveled to affix any materia to your gear. Culinarian is also extremely useful because high level food gets EXTREMELY expensive relatively quickly and offers a very respectable boost to your stats. If you're smart about it they'll also make more money than you put into them even if they are a little expensive to level at first.

The mount comes from a quest after you visit the 3 Grand Company leaders and view their respective cutscenes. Its a little ways after and if I can remember I'll get you the exact details when I'm home and at my laptop. Either way, it isn't VERY far into the story so you're probably there by now. You can skip the battle clear cutscene either by pressing escape on your keyboard or by pushing whichever button you have "cancel" set to on your controller. Comms are still done mostly because of the challenge log, you get gil for giving out so many each week =p Good thinking on SE on that lol

Sadly there isn't a way to check EXACTLY what spot the hunting log monsters are at. Instead when you highlight them it will tell you which zone and area they are in and you have to squint to read the squiggly lines FFXIV calls writing to find the area on the map. You eventually learn them all by heart but as another recent-ish newcomer I remember it was VERY hard for me to make it all out. You can also just do what I did and google the buggers, most of them are in one DB or another with exact coordinates.

Hope that answers all of your questions and if you have any more feel free to ask! Enjoy your time playing

[Kwoon]

Oh also, the sidequests. You CAN skip most of them but quite a few of them are tied to other content. Such as materia, triple triad challenges, non-storyline dungeons (and oh boy are there a LOT of them especially once you hit 50,) chocobo training (who needs a heal spell when you have choco regen and choco cure?) and all sorts of fun stuff like that. BUT, if you really don't like doing them my advice is to google the content you want to open and do the ones it tells you that you need. Personally, I saved side quests for classes I didn't like so I wouldnt have to grind them up myself.

[VisRalis]

Crafting your own gear isn't a good option. You should wait with the craft till you hit max level and even then it is only to save / make gil.

Would like to add to this: It's arguable not good if speed/lvling to max/progression is your concern - as you would have to take time away from leveling (and actually play the game's different aspect).

If lvling multiple classes as you go, being able to craft own gear, accessories and melding materia is a good thing (& satisfying).
It just takes time and you may feel more rewarding grinding dungeon gear drops rather than crafting.

[Malicewolf]

Saw that you weren't really looking forward to having to do other classes to continue playing the class you do enjoy. My gf was like that at first too. Now... well... let's just say she went a little crazy with all the classes (she pretty much has all of them now). You'll likely find that a class you didn't think you'd want to play ends up being really fun. If you want to make the best of your class, you'll often find you need to level one of your cross classes fairly high (usually high 20's or low 30's). For instance, swiftcast is a THM skill that all healing classes NEED so they can do quick raise's during fights. There's nothing worse than seeing a healer doing a manual raise for 7 seconds to be interrupted at the last second.

[Nhadaly]

The AI companions in main quests are just so weak, they die too easily, jesus.

Any way to help counteract this? I cant stand it.

They stand in everything, they shoot the stuff i CC, it was getting annoying but now they start to get pathetically weak as well?

[Ehr]

The AI companions in main quests are just so weak, they die too easily, jesus.

Any way to help counteract this? I cant stand it.

They stand in everything, they shoot the stuff i CC, it was getting annoying but now they start to get pathetically weak as well?

You shouldn't CC in instanced fights (the Main Scenario ones anyhow). They're designed to work for every job and not every job has the same CC, but every job can do damage. The best thing to do in instances is to complete the objective as fast as possible, which usually means killing the relevant mobs as fast as possible (or doing whatever other objectives they tell you to do). In most instanced fights there's always one mob that has a lot more HP than the others and you should kill the other mobs that are easier to kill before you bother with that one. Sadly there's not much that can be done about the AI (though it seems to have slightly improved in Heavensward).

[whiskeybravo]

The AI companions in main quests are just so weak, they die too easily, jesus.

Any way to help counteract this? I cant stand it.

They stand in everything, they shoot the stuff i CC, it was getting annoying but now they start to get pathetically weak as well?

Pretty much have to heal them and keep them up, or try to take on all the enemies yourself. Some quests are pretty cheap about stuff like that. If you're struggling with one in particular maybe try to level up enough to get your next ability/trait or next set of gear then try it again.

One other note, leveling with dungeons is the fastest way to level when you have bonus experience saved up (you get "rested" bonus from logging out in a sanctuary/inn room). As a DPS class, your queue times will be longer than that of tanks or healers, so while you are waiting for queues go to an appropriate area (such as Costa del Sol for lv30, Coerthas for lv35-40) and run some fates while you wait. Side quests are generally also quick exp, though in some cases you may want to leave a few for other classes when you level them.

If you haven't already, try to find an active Free Company to join. Most of the time people will help you run dungeons or help craft you new gear and give advice, etc etc.

[Malicewolf]

well, for me as a tank, i just took all the aggro on myself instead. This probably isn't a good route for you as a THM... you're a bit more squishy :P

What sort of instances are you referring to though? One thing to note is NPC's won't get out of AoE's. So interrupt spells and just simply turning enemies can often be very helpful for saving NPC's some hp. But usually going full offensive is the better route to take (usually). I've done my fair share of trying to keep NPC's alive instead of focusing on offense. The biggest issue I feel I run into is that for some reason heals to NPC's are VERY little... but their darn hp seems to go down too quickly in comparison to what you SHOULD be healing. It's odd. So try going all out on the enemies instead. If you still run into issues, you may need to take a look at your gear and upgrade it. Or level up to the level sync. Going higher than the level sync isn't bad either, it'll sync your gear as well, but the better your gear is, the better your performance will be regardless (unless you completely capped out on all of it).

[Naria]

Are you eating food? What is your rotation? Are you trying until the echo kicks in? After a few consecutive attempts the echo buff will start increasing your stats after every failure. As others have said, for the MSQ going on the offensive is normally best if you are a DPS. Also if it is not already I'd update your gear so that it is within 5 ilvls of your actual level.

[Iagainsti]

youll actually want to take it higher to get Quelling strikes, but don't worry about it to you get a better grasp of the game and understand how to level faster( Key words_ Food Buff, Heat of Battle II, Leves)