Having put together, and modded a lot of guitars in my life, just make sure that the nut is cut properly, that the neck and body fit is nice'n tight, and that t

Having put together, and modded a lot of guitars in my life, just make sure that the nut is cut properly, that the neck and body fit is nice'n tight, and that the neck is properly leveled. That should fix most errors. Learning how to level frets is a truly valuable skill for any guitarist. If a guitar is fundamentally sound (quality wood, straight neck with functioning truss-rod, good fit between neck and body), then a good fret-level and properly cut nut will clear most problems.