Files are a mainstay for us modders, because they remove material slowly so you can do some precise work. Personally I keep moving to different areas of the piece rather than totally finishing one area then moving on. To me it seems helpful just in case something is out of proportion. It easier to see a problem when the whole piece is at the same stage of progress.
Some inside areas may be so thin that you have to file away another area to get to them. A lot of the cuts on this next picture had to be done with the edge of a needle file, because of how thin the are.
The edges of a triangle file, put at an angle can help to get in corners or even filing a little from the back side can help you get in tight spots. I like to put bevels on things when it makes since, because it seems to help me line up the angles. Amazingly it almost seems harder to do square edges. Free form shapes are a good place to start, because you don’t have to match Identical angles as much. The spiky thing in progress has some of the areas beveled.
These projects don’t always look very good until they are painted or polished. Just keep in mind, first you are developing the shapes you want and the second stage is the finish on your piece. Chose your finish style and you can get some unique effects. With metal you can strip or sand off a blown finish, so go wild and see what you can create.
Dealing with Larger Pieces
When you do large pieces, a Dremel just isn’t going work very well. This is the realm of the Jig saw and the Band saw. I had to do a one piece window frame for The Metallica Build and I only had one shot at it, because of the price of a piece of Copper this big is $$$. I marked out and made the cuts very carefully. This would seem obvious but we tend to hurry things more than we should. On this big straight piece, every little wiggle of my Jig saw would cost me endless sanding to square it back up. Make sure you have a good Jigsaw! the blade should not twist from side to side very much or you’ll never cut straight lines. Use very high teeth per inch bimetal blades for metals. For Acrylic they make skip tooth blades that cut very well. If you didn’t know Cast Acrylic is the only way to go! Most other types of plastics melt to easy.