I've got several answers:
1. Not sure what you mean by favorite techniques. Basically, you take a an old, flat paint brush, dip the tip in the paint you want to dry-brush with, then wipe out all the paint onto a rag or paper towel, then LIGHTLY brush back and forth across the item you wish to highlight. The more you brush, the more dried paint you deposit, hence "dry-brushing".
2. All of it. Horizontal surfaces, or those exposed to the sun should get more than, say, the bottom of the hull.
3. Not necessarily. Any gloss coat will do the trick. Just make sure the gloss you use is compatible with the paint you put on. Future, being an acrylic (I'm pretty sure) is compatible with all paints, except maybe tempera or water-colors.
4. Again, not necessarily. Cutting the carrier film as close to the "painted portion" of the decal as you can, and drybrushing over the decal after it's mounted adds to the painted effect. In addition, the use of decal softeners, such as Micro-Sol or -Set helps decals snuggle down into panel lines, seams, etc.
5. What do you prefer? I personally like enamels, and the way they go down. Ask any other member of this forum, and they'll probably say acrylics. Experiment until you find something you like. Pick your own colors, and see what works. Colors will be predicated upon the era, country of origin, and duty location of the armor piece.
6. A few drops of paint and a lot of thinner. Again, I prefer enamels, and then oils. Washes should be runny.
7. Wherever raised detail meets a surface--as a rule--. I have put a wash over the entire armor piece to enhance coloration as well as define detail.
Please check in the technique and painting forum sections for more information--and don't get impatient when no one answers right away.....If you don't get a reply, the question may have already been answered several times in previous postings. You may want to check there first before posting your questions...At any rate, good luck with your modeling!
Gip Winecoff