If you look at it as having to get 560 crafting levels(with 210 gathering levels too so you can get your own mats) then it will seem tiresome or overwhelming. The key(well one of them) is to break it into segments that are more manageable. You can work on one or two at a time if you like. Or all of them at once, but only in 5 level increments. Or focus on some while passively leveling the rest. Or swear youre only doing a few of them, then break down later and do a few more. People tend to recommend doing all of them because there are really useful cross-class skills from all of them(not to mention being able to supply your own sub-combines). The whole tradeskill souls idea didnt get added until the first expansion afterall.

So suggestions? Well the first set of levels are really easy to get through. You can do 15 levels(the first cross-class skill) in under an hour per class without too much gil invested. After you sign up for the class, stand by the guild supplier NPC and start crafting. Theyll sell the mats required to get through the first few tiers of recipes, and just making each item once(this gets you bonus exp) tends to be enough to get you there. Stop for class quests(they give a ton of shards) as you go. Once you get past that there are still some easy gets for crafting exp. Once you advance your grand company rank a little theyll offer you provisioning missions - once per day(per class) theyll ask for an item. Turn it in, get exp. If its something they really want(marked with a star) get double exp. If you turn in high quality get double exp(these two stack). Buy the item or make it yourself(and thus get the exp for crafting it too). A HQ starred turn in is more then half a levels worth of exp. In addition to the GC missions, once you advance the story far enough you get the opportunity to do some side quests to improve relations with the local beast tribes. While most of them are combat oriented, there are crafting tribes too. These quests give you the materials and ask you to make something to turn in - and if you fail, ask again and theyll give you another set. So you dont need to buy or bring anything(aside from shards/crystals), just show up and craft. There are tribes for 1-50(the ixali), 50-60(the moogles), and 60-70(the namazu) - and the recipes for each are scaled such that any crafter of any class in the right range can do the combine. And finally, you can always toss in some leve quests too. These also reward HQ turn ins with double exp.

Theres a lot more i could say, but that feels like a good start. Best of luck!