First of all, welcome to a great class to play and to this awesome forum. There are a few good class sites out there, but I think this is far and away the best site, period. I've played EQ for 4 years now, and I still visit the shammy forums almost daily for 3 years now. Samanna is super organized, and the info you can find here is overwhelming, and not just for the shaman.
There's going to be lots to learn on your shaman in several areas. Having played a warrior main, I'm sure you're at least aware of the various roles different classes have. The shaman is so versatile that he fills almost any role at some given time. How far you push yourself depends totally on your mindset -- are you content with being a background shaman, and just slowing and patch healing? Maybe you prefer DPS. You can play thru the eyes of a crowd controller, solo like a necro, or even just play main healer. Maybe you like the challenge of pulling. Shaman have the tools to do at least a decent job in all these areas.
For now, as you warm up to the possibilities, and scour thru some old posts here, you'll at least want to concentrate on a few areas. These are what I suggest:
SPELLS: Get all the spells you can. Grind/MM your way up to 65, then stop here to get spells and some AAs. Personally, I'd say before you grind out 23 AAs for Canni5, get Virulent Paralysis (punt-root the mob) and your 9th spell gem. Make sure you at least have Malo/Malos, cripple, our best quick heal, and Quiescence. After that, turn your back on MMs and learn to play the shaman properly.
TACTICS: Make lots of and learn to use
hotkeys. Be able to target anything quickly. Know and control aggro. Memorize 10 different spellsets, and learn to use /mem spellset on the fly. Here's a simple guide you can use to get up to speed:
http://www.rpgexpert.com/1844.html
GEAR: Thru the bazaar, spend 30k or so to make sure every gear slot you have has at least 50 HP. Focus on HP; the stats and resists will generally be good on high HP gear. Endgame most of your stats are gonna be max anyways, so don't worry about searching for high +WIS gear atm... it will come. Remember, for shaman and necros, HP = mana.
There is much more info, such as zones to hunt and specific gear/focusses to get, but I don't want to write another novel atm. To wrap things up for now, keep these in mind:
1) Keep your eye glued to group health bars. Be ready to heal anytime.
2) Watch for adds. Root them, slow them, punt them, off-tank them.
3) Be pro-active. Malos the mob on inc BEFORE the tank has aggro. Slow not long after that. If main healing, keep an HOT on the MT before the pull comes in. Cripple early if needed, and DOT early if DPSing. The second half of battle you spend regaining mana, handling parked adds, going to pull, etc.
Good luck and post whenever you have a question.