a) I wouldn't worry about it too much.
b) throw out things that sell for nothing to make room for things worth money - except beastman seals. (so things like flint stones etc, though as the below poster said everything adds up, it is often not worth your time to trek back to town just so you don't toss junk - balance time spent to worth. More time spent walking to town is less time spent farming profitable mobs)
c) Beastman seals: SAVE THOSE. They can make you more money later. Also there are npcs in Jeuno that can store them for you so they won't be clogging your inventory forever.
d) the "honour" as you so call it (more commonly called "fame") actually will help you expand your inventory so don't look down on it. You need a certain level of fame to unlock quests to expand your inventory
e) Save up around 10K. Yes. That does sound like a lot of money, now doesn't it. However, you can use it to buy a mog sack from an artisan moogle. This gives you a second inventory with as many slots as your main inventory. You can get ANOTHER one if you get a "security token" so even if you don't care about your account security it is worth getting for the inventory alone. SOME low level drops worth saving
(All prices current for Asura, other servers will vary) Honey: 10K a stack Wild onions: 2K each 30K a stack
(These drop off Goblin Thugs) Silk Thread: 1K each, 30K a stack Beehive chips: 15K a stack
Crystals also sell fast. Check what the AH price is before listing them, then list them, perhaps shaving off a couple gil to get them to sell faster. Always wear signet. Also get yourself a few more levels (15 is good), then go party in gusgen mines (don't worry about your gear, no one cares) - you will get a gil bonus every time you complete a page
There will be a book at the beginning of the dungeon, shout "Book Burn Party, please invite me" or something, flag up, and you should get in, then ask them what page and interact with the grounds tome, select the training regime matching the page they told you to get (page 1 or 2). Select "yes" when it asks you if you want it to repeat.
Each real life hour you'll get some gil when you complete the page.
Also if you see a skull drop while you are in gusgen, let people know you need it for your subjob quest and lot it. Otherwise, it is considered rude to lot random trash while you are in parties, so if you need something, let people know before you lot and don't just lot everything. The game will autolot it for everyone. Edited, Oct 5th 2012 2:07pm by Olorinus