I have a question on how to fix a bike?

I have a 18-speed Next Bike it is in pretty good condition other than some rust, but when you are riding in any gear after about three full pedals it clicks. What I mean by clicking is that is clicks like you are changing gears even though you arent. I was thinking something was wrong with the cable. If you know anything about bikes I would appreciate you answer my question. I'm needing to know what the problem is and how to fix the problem if it is fixable.I have a question on how to fix a bike?
The clicking is because the derailer is not aligned perfectly with the sprocket the chain is on. It is trying to change gears.



You can fiddle with the adjuster screw until it goes away or take it to a bike shop and pay then to adjust it. Sometimes it is worth it because those things can be so aggravating.



You also might want to add new cables since if there is any rust or anything in them, they might not be adjusting 100%I have a question on how to fix a bike?
Click this: It gives you complete instructions on adjusting your derailer.

http://www.sheldonbrown.com/derailer-adj
There are a few things that can cause this, but they are all pretty easy to fix. First the cable could be stretched, buy new derailluer cables.. you won't need expensive ones, there is hardly a difference unless you are racing. Next tune the derailluers. Goto http://www.utahmountainbiking.com/fix/index.htm if you don't know how to adjust them. If you are riding an older bike replace the chain too, it will make a big difference in performance. I would suggest doing all these things on an older bike or a bike that hasn't been ridden in a while. A lot of bike shops can do it for you, but they can get pricey, you should be able to do all that yourself for $20-$30.