It’s all about timing.
Polish that goes on over a color coat that’s even slightly soft will drag and streak no matter how well you brush it, and how fast a coat sets depends on how thick it was and how warm the room is. Humidity wrecks a manicure faster than anything else. The good weeks were the weeks I happened to wait long enough.
Now I do one hand, then the other, and only start coat two when I’ve done the full loop, so each nail gets a proper few minutes. Yes, it takes longer, but it’s a lot faster than having to redo everything or paying to get them fixed because I rushed and made a mistake.
And the lighting matters! Salons have those bright, flat lamps pointed straight at your hands for a reason.
If you paint under a bright desk lamp, a cheap daylight one angled low, you see the drag marks while the polish is still wet and can float a bit more over them before it sets. If you do them in the dark with your laptop or TV light, you’re going to see your nails in the morning and wonder “how did I not see that before?”
A lot of what reads as ‘done’ at the salon is the skin around the nails. Hydrated cuticles, no ragged bits. A slightly imperfect coat still reads as polished if the hand looks tended to. There is good advice for a nail care routine here and this will do so much of the heavy lifting for you.