This should probably be in the detailing forum.. but:
What color is the car? You will probably want to apply a coat of sealant (lasts 3-6 months) and then top it with a coat of wax (lasts 3-8 weeks depending on the wax). This will give you good overall protection.
'15 i3 REX // Capparis // ZGW // ZTD // HK // 20"
20% Tint, Coding, LED High Beams/Signals, Painted Reflectors, MAX2 Hardwire
Past: F30 335i, E90 328xi