As my Z3 had some really rough paintwork.. It felt like a rough paper.. I got the first real polish done by the professionals. Also so I could watch and learn what he did. Washed, then clay bar, then washed again, Black polish with a mop, then washed, White polish with a mop, then he washed it again.. used a pad with some autoglym prep and then applied the Autoglym HD wax. The finish that he got was so deep and amazing. So if you are unsure , get a professional to show you the way. The Estoril Blue as shown in my profile photo shows you how deep a shine you can get even on 14 year old paintwork.
An investment in the future for me and it was worth every pound.