Future is a great product to use just after painting and before decals are added. It supplies an optimum smooth, glossy finish for good adhesion and no silvering. Makes a good floor wax too, I've heard!
Future can also make a FLAT or semi-gloss finish if you add products like Gunze Flat Base or even talc.
You don't need a lot of glue between parts to hold them. Don't be stingy, but don't flood the parts either.
Need a metal finish? Look at SNJ powder with regular silver paint - or other colors! - or BareMetal Foil. They're more durable than most other Metalizers.
Small canopy scratch? Try filling it by dipping in Future!
In Europe and can't find Future? Use Kleer!
Have a molding seam down the center of a canopy? Sand it out - with progressively finer grades of sandpaper. End with a polishing kit, and/or Future.
Take care of your brushes, and they'll take care of your finishes. Clean and store them properly.
Don't just tear parts from the sprues. Use an XActo knife, or better yet, invest in some sprue cutters.
Need information on a model, details, or have a question on finishes? Head to Google and use their "Groups" tab. Search on rec.models.scale with your question - it's probably been asked already.