For me, one thing that bugs me is mold seams. They will make or break any model in my opinion. I will sit for hours cleaning every single part of mold lines, and getting every part to fit as perfectly as possible. If it's a chrome part, I'll just Alclad it when I'm finished. One thing to always remember is to give yourself room for whatever paint your using, for instance, if it's just a light coat of metalizer, that part will fit good, but if it's paint, or an Alclad finish, that part will grow with every coat, so you will need to keep that in mind, and remove more material before painting.