I have come a long way from my first days of working with CAD and machining parts. I learned a lot from professional advice, reading books and articles, and working in the real world, but I've definitely learned the most from my own endeavors. I'm not a "pro" yet, but I felt that Pro Tips is a cool name for small lessons that I've learned from first or second hand experiences.
Deburring Pro Tips:
Deburring seems like a simple process that won't change the outcome of a part, but after ruining the asthetics of countless parts when trying to clean off the sharp edges I learned it takes as much skill as making the part in the first place.
-File long edges all at once
Long edges can easily show marks from multiple file passes or an inconsistent cut with a deburring knife. When you have a part with a long edge try orienting the file parallel with the corner and lightly file the edge until it won't cut your hand. This leaves a machine-like small chamfer. This is very important for acryllic or polycarbonate.
-Avoid deburring knives.
I know they can remove an edge very quickly, but almost every time I have seen one used, it ruins the part. File straight or convex edges with a light touch. If you have a hole, use a countersink. If there is a concave edge that can't be filed or countersunk, then you can use the deburring knife. They are really only meant for concave surfaces, so they work acceptably if you are careful to maintain a consistent chip.
Polishing Pro Tips:
I like a "well polished design" to be both figurative and literal. Polishing is a big pain, but sometimes its worth it on a project where aesthetics are a big concern.
-Wear a face mask and goggles
Polishing is messy and I can guarantee that you will get something in your eye without goggles. Polishing also kicks up a lot of fine particulates. That can't be good for your health, so wear a mask.
-Sand before polishing
Aluminum and other metals don't have much material removed by polishing, therefore it won't make the part shiny. I've found for aluminum starting with 200 grit sandpaper will get the surface uniform, 400 grit will get it very smooth, and then the part will polish to a semi mirror. Additional higher grits can make the finish even better.
-Use a purpose polishing compound
I needed to clean up some icky looking polycarbonate. Plastic polish worked amazingly well. I've also used aluminum polish. It worked considerably better than generic polish.
Design Pro Tips:
-Set screws suck... don't use them. They don't have enough surface area to grip a part very well. They put a lot of force on a small area, which almost always dents a part. If a set screw slips it will always ruin the part it is gripping. I always try to use clamp collars or other alternatives to set screws.