First off don't use washing up liquid ! Use these steps for a hand polish/detailing and you won't go far wrong(body only)
1:wash car (strong shampoo mix)
2:decontaminate car with fallout (iron) remover
3:rinse then repeat again with tar remover
4:rinse
5:clay full car(fine clay) Meg's system is fine
6:rinse ,wash and dry full car
7:use scratch remover very carefully on bad marks/scratches
8:give the car a coat of autoglym SRP or AF triple
9:wax car 2 coats if time permits
10:use AF finale quick detailer or Meg's quick detailer after every wash to maintain and top up shine