is there another exp potion outside the one from your garrison you can buy without exalted rep and such?
Don't think so. If you haven't done so, grab 75 coins from Lunar Festival (last day), buy robe/tunic/BP heirloom and upgrade to 100 so that you have +10%. If you've got cash buy the rest of the heirlooms.
anyone got a good guide on garrisons? basically looking for something to hold my hand and take me through what I need to do in order to get the missions and be successful, ive pretty much ignored my garrison.
Guide: follow the quest lines to grab as many followers you can, do Garrison Resources missions first if you're leveling fast, gold missions/personal XP first if you're levelling slowly, follower XP misssions first in-between.
Build whatever profession building you have as first small (pick one if you have two crafting prof), or ench. if you have only gathering prof.
When you get the quest to upgrade your garrison to 2, pick Lumberyard if you're leveling fast (now that it's 30 GR per WO, it's good) as you'll need lots of GR, pick Inn if you're leveling slow (to get more followers that you're not getting from quests). Pick the second prof / ench. / keep empty.
When you're 92, open up your mine, upgrade it, then go immediately to Gorgrond, do the two outpost quest lines up to the scenario to get an upgrade to your medium building. That unlocks most trees you'll encounter for Lumberyard, or you can start recruiting followers to fill holes in your roster, depending.
When you're 94, go immediately to Talador, follow your outpost quest line up to the Ogre boss to get an upgrade to your barracks, you'll get to pick a follower for additional DPS/tanking. Grab the BE/Draenei chick near Auchindoun NE entrance, as that's the quickest follower you have.
Now, coast toward 100. When get into Arak, pick the Brewery as your outpost, there's now absolutely no good reason for the Smuggler den unless for some reason you want to spend gold on an overpriced bag. When offered the quest to go to Sparksprocket (??? I think), go there, pick the plans for recycling building. Use your outpost upgrade to get the level 2 for that building. If you already have two smalls, wait, otherwise, start building.
At 100, upgrade your garrison as soon as permit, build/upgrade your recycling center to 3 as soon as possible. Pick second medium and second large building to fit your tastes (I tend to suggest Bunker/Warmill for second large). Upgrade Barracks to 3 as soon as possible to expand your follower roster to 25.
Now for the followers: Master Plan is absolutely mandatory. It will let you build teams quickly, and make sending out followers. You want to collect as many weapon/armor tokens to upgrade them from 600 for ilvl 615 gear, 615 for 630 gear, 630 for 645 epic gear, 645 for highmaul raid gear, 660 for BRF raid gear, which is why the recycling center and bunker/warmill come into play. The only problem of bunker/warmill is that you need to spend GR on it, so if you leveled quickly, don't pick that one because you're still spending lots of GR to upgrade your garrison.
Master Plan will tell you what followers are most likely to be good at raid missions. You need to upgrade 3 to 645 to unlock them, so upgrade the 3 that appear in the most missions, check which mission you actually get, and upgrade the rest. Master Plan will also tell you what followers have the same abilities counter as another, so you can reroll one of the two (using a full reroll, or just an ability reroll).