Meguiare's is a very nice product.
Try these steps:
Wash with a product u use in the kitchen (to get all the old wax etc off)
1. NXT car wash
2. Scratch X
3.
DEEP CRYSTALŽ SYSTEM POLISH
Deep Crystal polish
4. NXT tech wax
It's also very important to use a good wash mit + towels (microfiber)
Takes a few hours to do but the result is amazing.