well I am no pro but I picked up a few things over the years
I hired a guy he was right at the end of his carrier to paint my first house 20 some years ago watching him I learned a bunch , I hired him at the time because I didn't have the time it was living room , dining room , stairs and upstairs hall a big project to get done with a pregnant wife and toddler at the same time.
the first was 4 1/2 and 6 inch rollers , there are few places you can't get with these and you can go right up tight to a tapped edge
https://www.homedepot.com/p/Wooster...Frame-Roller-6-Pack-0HR9830044/204354009what kind of paint do you have ? latex or oil or epoxy , something else ? oil will often apply better to flat surfaces when you mix in a little thinner , you may still need 2 coats but thinned a little it flows so much better.
with latex paint wet down and ring out the roller first before it touches paint this takes up the volume of the nap of the roller with water and then it absorbs less paint , it also helps to smooth the first few rolls
2 coats is often the case , but with the rollers you can lay it on thick around your taped edges and then only get close to the edges on the second coat and typically not have issues.
what your covering makes a big difference.
surface prep is huge , clean , dry , ruffed up with some sand paper if it is trim or wood
that was one of the things George the painter talked about he detailed cleaned the exterior of peoples houses before painting , some he would be getting don with that the first day and they would say , wow it looks great , I can't believe your done so fast , he said no I just scrubbed and bleached it to get ready for paint.
Goerge was not a fan of pressure washers , he said they just pushed water into the wood fiber and that had to come back out later and when it did it caused issues
TSP and or bleach if it was mildewed a scrub brush and a regular garden hose to rinse was what he used.
I think he said if you had a few weeks to pressure wash wait then come back and paint they might be OK but that wasn't how jobs worked.