Here's what I found the easiest and best looking results when I use the claybar/wax. If I managed to forget anything, I will edit this post.
1. Wash the car twice with some Dawn dish soap. It will remove pretty much remove any wax that is there.
2. Dry with your choice of towel or chamois. I use the real rawhide chamois.
3. Drive the car around the block to get rid of any "hidden" water.
4. Dry off any water that came out.
5. Get your Mothers or Meguire's Claybar Kit. I prefer Meguire's.
6. Spray the whole hood generously with the Detail spray that comes with the kit.
7. Mash the claybar into a ball then flatten out so it is about 1/2'' thick. Push the claybar onto your fingers.
8. Start rubbing the claybar onto where you just sprayed in a back and forth motion or "wax on, wax off" motion. Make sure you do it real good. The longer you do it, the better the results. Don't go try and take the clear coat off though. After every section or when it gets too flat, make it into a ball and repeat step 7. DO NOT DROP IT ON THE GROUND!!! It will pick up every speck of rocks, even stuff you can't see. It will scratch the shit out of the paint. If it does hit the ground, try to get every speck of the rocks out of it or replace it.
9. Immediately after you finish the hood, get one of those microfiber towels and wipe the spray off until it is mostly dry. I then use a regular cotton towel and finish wiping the surface until it is dry.
10. Repeat steps 6-9 on the fender, then door, then roof, then rear, then other door, then other fender. Reason to do it in sections is so that it doesn't completely dry.
11. It's best to do this on a fair temperature day. Around 70-80. Also, if you can do it out of the sun even better. The sun likes to bake on the clay after you do it which makes it really hard to get off. Very noticable on darker cars.
12. Now's the time to put your tire shine on if you use the spray or aresol type shines.
13. Lastly use your favorite brand/type of wax. I prefer Meguires NXT generation wax (purple bottle). I would like to use Zaino's, but it is a little to expensive for me.
14. Use a oribal buffer if you have one. You don't have to put a lot of wax on. Sometimes less is better.
15. After you have put all the wax on, take it off with a microfiber towel. I usually use the polishing pad for the oribal buffer after I use the microfiber towel. But, if you don't have one, just make sure to get all the wax off.
16. Crack open a beer because you are going to need it after all the hard work you put into the detailing.
17. Stand back and look at what you have accomplished. Rub the backside of your hand along the surface and you will be amazed at what the claybar can do.
**Disclaimer** This is what I always do and it yields very good results. I'm not to be responsible if you don't follow the directions and mess up your paintjob.