With nitro lacquer.... one key is to not apply too much lacquer. Lacquer takes breathing room to dry. The thicker the coat, the worse it is. When its thick, the top dries first and makes a non-breathable layer over the bottom. So its important to let the coats be THIN, and I mean THIN, just barely wet. Let it dry FULLY before new coats are added. If you dont, just like before, you trap gassing-off lacquer under new lacquer... the new on top infuses the bottom with more solvent and the whole thing takes even longer to dry.
For DIYers, lacquer is easy - provided you take your time, and let it dry and dry and dry.
If you add up a bunch of quick coats, and have no special nudie bar tanning bed to dry it in... it can literally take months and months to dry.