When you start cutting you need to secure your piece. One little slip with a Jig saw or Dremel can cause a lot of work or leave a none repairable defect in your piece. At first I will leave additional material on it so I can screw it directly to my work bench. Clamps can do the same thing, but they tend to get in the way more. Ohh my poor work bench!
Cut outside of your lines and file down to the final lines. Use drills to get inner holes to start filing. When you pick a drill size go smaller than you think! Those bits just seem to get closer to your final lines than you expect. Remember you can’t go backwards on this type of stuff! you can always cut or file a little more, but you can’t uncut a line that went a little to far. Saying that! the bolder you are with your power tools, the less filing you will have to do later. Be careful! I hate to see grown men cry. especially me. At this stage of a project it looks terrible. I’ve had several pieces that I swore I’d blown it on, but I just kept chipping away and it all comes together when your finished. When you are working a piece so long you see every little imperfection. The good news is that they almost never show up in the pictures. We are not perfect CNC machines but we can make some cool stuff anyway.
Try not to do the weakest areas until the end, so you don’t damage that area working on another area. I will use my Metallica emblem as an example. I wanted to make this in one piece so it would be easier to mount. The connection between the C and the A was going to be extremely thin, so it was the last area I cleaned up. When your filing an inside area, keep working all sides a little at a time. Take a rectangle for instance. If you file all the way to the bottom cut line, when your filing the Sides you are at risk of expanding the bottom further than you want, when you get down to the corner. So take material away on each side a little at a time. It also lets you see if your shape is off course.
Because this is time consuming I do most of the filing at my computer desk so I can watch movies or what ever to pass the time. Use adjustable clamps and protect your desk with a thin piece of wood of plastic if necessary.