I'm entering this in the Epilog Challenge. With an Epilog Zing laser I could make my miniatures much more detailed and outstanding.
Step 1: Supplies
A piece of wire about 2 feet long or so, malleable enough to be able to be bent with your fingers, but not too easily.
Pliers, with a small tip.
A reference image. I used http://olveramusic.com/images/fotos%20instrumentos%20grandes/trumpet%20picture.jpg
Copy your reference image into Word, Paint, or some other program and shrink it until it is about 2 and a half inches long on your screen. You can print it out if you like, I prefer to save paper.
You will hold your work up to your screen along the way to make sure your scale is right.
Step 2: The Mouthpiece
Take your pliers and grab as little wire on one end as possible. Twist the pliers around making a hook shape. Squeeze the hook with your pliers to make it as small as possible, trying to keep the sharp end tucked in. Bend the wire so it is perpendicular to the curl you just produced and now you have a mouthpiece!
Step 3: Tuning Slide
Step 4: First Valve
Hold your wire up to your reference picture, where the first valve should be, make a bend downwards (picture #1). Then, once again comparing to your reference, make a sharp bend upwards (2). Then another sharp bend downwards where the top of the valve is (3). Then bend the wire backwards where the valve cap would be (4). To make the top of the valve, bend the tip of the curve you just made so it is flat (5). Then start winding (6, 7), if the coils are too loose tighten them with your pliers. Keep winding until you get to where the valve slide is. Just bend the wire outwards and back and continue your coil (8, 9, 10). Now stop and straighten out anything that has gotten out of whack during this process.
Step 5: Second and Third Valves
Same as with the first, end your wire upwards, downwards, bend the tip forwards, wind, and straighten. This time the valve slide is considerably shorter and points towards you. Refer back to the last step for anything specific. Repeat for the third valve.
Make sure you are comparing to your reference picture often.
Step 6: Bell
Where the wire passes the last valve, make a bend. You will be doing the same thing you did with the mouthpiece except with more wire. Make a tight coil like how you did when you made the valves, except this time you don't have a wire running down the middle. Continue this coil referring back to your reference picture about how long it should be. Mine's a little short because I ran out of wire but hopefully you won't have that problem. When you get it to the shape you want it to be cut off the end with some wire cutters and bend over the sharp edge so it's not sticking out.
Step 7: Finishing Touches
If you were using old wire, like me >.<, and it broke, then just glue it together with a little super glue, it won't hurt.
Now you can attach a chain or put it in a nice case or on a nice stand and show it off! :)