Okay a couple things to try:

1. Check and see if an NPC is selling a basic version of what you are looking for. Then, if you want to upgrade it (either by adding materia and/or changing it from ____robe to a ____robe of casting, all you need to do is ask a crafter either in your ls or via /sh in town.
2. Do battle leves for leveling your battle class (thm) Every now and then, they drop a piece of low level gear that you can use.
3. Around rank 30, there are 'little' NM's that drop equipment you can use. Also, if you have access to toto-rak, there are some nice pieces in there. (You will need either a party or one level 50 friend to get this gear)Some notable pieces include:

Thalassian Targe: Shield Opt. Rank 25 (MP : +5, Int : +1, Pty : +1,Magic Evasion : +10) Dropped from Slippery Sykes
Seer's Cowl: Opt Rank 35 (MP : +30, Mnd : +4, Pty : +4,Att Magic Pot : +4, Magic Acc : +4) Dropped from Prince of Pestilence
Anathema: Opt Rank 35 (MP : +24, Int : +4, Attack Magic Potency : +17) Dropped from Unknown Soldier
Ascetic's Tights: Opt Rank 30 (HP : -9, MP : +9, Vit : -2,Att Magic Pot : +2, Evasion : +3, Magic Eva : +5) Toto-rak chest

Another pro to farming these items, is that when you're done with them, you can turn them into your guild company for seals (How you can get a chocobo).

4. Level your crafting via local leves. This way, you don't burn any mats/shards. Also you will be rewarded mats you can use each time you do a leve. (You can use these mats to make your own gear/make gears people buy fast for Spiritbonding.

5. Ask around in your ls if people have anything they can loan/make for you.

6. If nothing else, keep your weapon upgraded and eat food to boost your mag acc/int. At least that way you can solo effectively.