Step 1: Taking the Guitar Apart
Start with the strings. Unwind each string until it is loose enough so you can remove them from the pegheads. You can then take the bridge(s) off, if they are held by the strings.
Note: You may have to cut the strings with pliers to get them off, thats why you should have a new set.
After the strings are taken off, unscrew the big screws on the back holding the neck to the guitar. Since I don't know every part of every guitar, you will have to figure this part out for yourself. Once you are left with the body, take the parts holding the pickups off, they are usually attached to it. Then, take off the pickguard, and then carefully take the electronics knobs off by pulling them off. On the electronics there should be some nuts holding them in place, so take them off. Now on the back, take off the covers of the electronics, tape the open holes with painting tape, carefully push them back inside so they are inside the space, and put the cover back on. I do this because I didn't want to snip the wires to take them out, so I put them out of the way instead.
Now, for the pickups, I covered them with a tissue, then taped around it with painters tape. I then put them back in the "hole" were they came from upside down, and they fit in there fine.
When you take apart the guitar, you should get styrafoam cups or containers to put the loose screws and parts inn, so you don't loose them. For reassembling reasons, it would be a good idea if you took a picture of the screws before you took them out of the guitar so you know were they go and what you might be missing.
Another thing you might want to do is see if there's anything you might need to replace, so you don't have to do it later.