Two quality OTC products I've used are Meguires and Mothers.
Steps;
1. Wash with 'Dawn' dish washing liquid to remove prior wax.
2. Clay, using a mixture of car wash/water solution.
3. After claying entire vehicle,wash car with good quality car wash and dry.
4. Begin polishing. A good coat of Meguires or Mothers wax every 6 mo. for a daily driver is sufficient.
I don't use "sealer" waxes.
If using wax, I prefer to do a car every 3 months.
Also, be sure and use good quality wash mitts (sheepskin or chenile) as well as towels for drying/polish removal.
Please let me know if you have further questions.
Ed