Ben, its been a while since I've done A/C modeling, but I have a collection of about 200 built 1/72 WWII planes, plus maybe another 50 unbuilt. I moved to WWII armor models, but have not had a lot of time lately to do any.
Tips : I hated to do it, but this is a MUST ---- spend the money to get the tools. I only wanted to buy kits, but if you really want them to look great, you have to have the tools.
If you're gonna do airplanes, you have to have an airbrush. Spraycans will work, but it covers too thick. Also, cans limit the number of colors you can apply. With an airbrush, you can spray any color there is, plus mix your own colors if you need to. Cans work great for armor. An airbrush and compressor is a pretty big investment, but nothing works better if you are seriously building models. Most important point if you do buy one; KEEP IT CLEAN. Buy thinner by the quart, you'll use it. As an aside to this, make sure you have a nice, well-ventilated place to do any spraying ... the fumes can mess you up !
You should never have less than 5 packs of brand new Exacto No. 11 blades. Lots of masking tape, sanding paper in various grits, files, GOOD quality brushes for detail work, and SUPER-GLUE is your friend ... just remember not to use it to attach clear parts, it will fog them like crazy.
A good filler is a must to eliminate seam lines where parts like fuselage halves glue together, or where wings dont exactly fit to the body. You have to practice filling seams and sanding them smooth where they dont show under the paint job.
Buy lots of plastic shapes, sheets etc ..... experiment with scratch-building lots of things with this. Engine mounts, instrument panels, fuselage stringers, throttles, EVERYTHING. You can buy aftermarket stuff, and sometimes it is the best way to go, but it can be costly. Easy to spend twice as much on aftermarket stuff as you did on the kit. Learning to scratchbuild stuff not only saves money, when you do something and it turns out looking neat, no better feeling in model building. PRACTICE !
Spare time on the internet is always spent Googling aircraft, and especially the Image Search feature. Look for pics that show up-close details. Any time you run across a plane pic showing good up close features, SAVE IT in a special file on your computer for later reference. Google keywords like " P-51 radiator ", or B-17 landing gear ", but look at any website, anything that has aircraft pics with a mind to finding close-up shots that can be used in building a model accurately.
Also Google " P-51 walkaround ", or whatever plane your wanting to see pics of. Modelers have several websites where guys go out and take up-close, detailed shots of planes in museums and post them for modelers to use as references.
Heres a link to one example I found by Googling " ME-109 Walkaround "
http://www.aircraftresourcecenter.com/AWA1/001-100/walk037_Me-109_G-10/walk037.htm A subscription to a good model magazine is well worthwhile. I always subscribed to Finescale Modeler. Altho it covers everything from planes to armor to sci-fi, the techniques described in building any plastic kit will help.
The model forum here is good, always check it regularly. Another good modeling forum is at this link :
http://www.ww2aircraft.net/forum/modeling/ Spend some time looking around the International Plastic Modeler's Society website, the PREMIER place to find information on models:
http://www.ipmsusa.org/index.htm and their link page :
http://www.ipmsusa.org/Links/Rpt_SIGS_Aircraft.htm Basically, to build model A/C you are gonna really be happy with takes lots of practice, and spending the money on the tools needed instead of just on more and more kits.
One specific technique I remember, since you mentioned the silver paint for worn/chipped metal edges :
Cut very thin aluminum foil to shape of wing leading edge and glue in place, making sure it lays flat on the model surface. Foil edges should be on panel lines so they are not apparent after painting. With the tip of a toothpick, apply melted candle wax in desired paint-chipping area of leading edge on the foil. Dont over-do it. After wax cools completely, spray camoflauge paint and allow it to dry for a couple of days. When paint is completely dry, use low-tack tape to lift the wax off the foil, leaving the metal showing through the paint. This technique gives a scale appearance of chipped paint because it shows the " skin layer " under the camo paint instead of a silver paint OVER the camo paint.