How do you keep up with gear 1-60?

Im leveling a human rogue atm and im level 10 with full white gear,

I was wondering how difficult the content gets as you get closer to 60 with awful gear?

I also wanted to know when to move to the next zone.

Personally, by level thirty I gave up on attempting to maintain my gear, when you reach closer to TBC it does become noticeably more difficult, but this may depend on your class as I leveled prot pala.
Tips:
1. Focus on reaching tbc content by any means necessary, tbc greens will easily outfit your gear, try to be patient.
2. Don't quest as you normally would on a 1x rates, skip any quest that is overly time consuming (follow quests, well known low drop rate quests and the like that people always farm, like the zanzil elixir in stv).
3. There are no achievements in TBC so again, refer to #2, it's just a time sink.
4. When you reach outlands, focus on hitting 70 rather than completing a zone, quests give more gold once you are level cap instead if xp.
5. In regards to changing zones, it all depends on your preferences, I've skipped entire zones simply by killing mobs trying to finish a "collect x amount of this" quests, refer to # 2.
6. Have fun.

Use the auction house to buy gear, it's the only way you can. Make sure you have an alt near the auction house that you mail white and green items to. I highly suggest using auctioneer to sell all the stuff using the appraiser. Also get an addon to open all your mail for you.

These are great tips everyone I've learned a lot from these thank you all.

get skinning and mining at start its money making machine for low levels.then simple buy weapons from AH and you good to go:D
ofc your goal is to get to 58 asap and move to outland but keep in mind if you fight lv 40+ mobs as rogue with lv 10 dagger you most likely wont kill it or will take ages to kill single mob.i remember someone telling me when he was leveling his rogue,every time he killed a mob he waited for his evasion to get of CD before he pull next mob in un`goro.rogue and warrior are by far the hardest to level in TBC,but they really good on lv 70 so its worth the pain :D

You just to have decide wich quest you should do, with my rouge, i did quests wich are green for kill quests, or quests wich say kill one mob xy (there were plenty ppl arround to build a group with) i changed the zones a lot just to pick the best and easyiest quests.