Congrats on the BMW pick up. Black can look amazing when properly detailed, but it can also be an eye sore if there are tons of swirls in the paint.
The first thing you'll want to do is invest in quality washing and drying products and
learn the proper washing and drying techniques. Swirls and other imperfections typically occur due to improper washing and drying techniques or using dirty or ineffective equipment. A good starting point for you would be
this wash kit paired up with a couple of
5 gallon buckets if you don't already have them.
If you want to ease into detailing without investing in a buffer to remove swirls but still want to add more depth and gloss than you currently have, I'd recommend going a glaze then topping it with a sealant. This is easy as applying both products thinly and removing them with some
quality microfiber towels. I'd suggest going with
Chemical Guys EZ Creme Glaze then topping that coat with some
Blackfire Wet Diamond.
That would cover your paint, beyond that, you'll want to pick up some stuff for your glass, wheels and tires, and interior. Some of my go-to products for those steps are...
Chemical Guys Window Clean
Optimum Protectant Plus (cleans and protects vinyl, rubber, leather and plastic surfaces)
Meguiar's All Purpose Cleaner (great degreaser and works outstanding on cleaning carpets, tires, wheel wells, engine bays and virtually any other stained surface when diluted properly)
Poorboy's World Bold 'n Bright Gel
That should be a start for you. If you have any other questions or would like any other suggestions for specific areas of your car, please do not hesitate to ask.
George