ok guys help me out on this one. we all got to pitch in here and we can make a list of uber important tips.
my absolutely best tip is this
if your cutting from a design.. make sure its centered (or wherever it has to be) then tape it or mark it or whatever. then make sure again.
this will burn you if your not careful!
get safty goggles if your going to be useing power tools. ya you might look like a goof and it may be an extra cost and inconvienace, but not being able to see is more of one. play it safe.
nothing is perfect, but you can make it pretty close if you pay attention to detail.
always remember there are parts of your pc people will almost never see. you dont need to spend so much time on those places.
be patient. rushing through something because your excited to be working on your newest idea is a bad idea. take your time, do a good job rather then doing a crappy job and then haveing to fix it.
look at what your doing before you start. you dont need to plan the whole thing out if thats not your style, but you should definately look at what you want to do and see what is going to be complications and their solutions BEFORE you get too deep.
if your cutting some metal that you have to paint later, sand it before you start cutting. that way you wont get sliced when you sand.
a long preperations usually equates to a good finished product.
dont get discouraged if something dosent work. just look at why it didnt work and make it go your way.
you will never be able to find a tool you need when you need it. get in the habbit of keeping your workstation clean.
when your cutting something be conservative about your cuts. its alot esier to file things down cause their too large then have to go back, get more material mark it out and cut it again.
ask your friend / gf / wife / coworker some time for a left handed hammer or screw driver some time and see if they clue in.
even the most complex problem is just a serise of smaller probelms. break them down and handle them individualy and your set.
things are only as complicated as you allow them to be.
when painting, prime your work. and seal it when your done.
be creative. ya ok, you have a problem. look at it. think about it. think about what other materials you know about that might help you. if your totaly lost for ideas, welcome to the internet. vast welth of knowledge here. lots of products that do things you hadent even thought of before.
nobody is pefect all the time. look at mistakes as oppertunities to learn a new way to fix something. in the end of it you might just use the new skill you learned to fix not only your mod but something else arround the house.
whos arround? although probably the people arround you arent computer modders, everyone has a profession. maybe you know someone that builds metal things in a factory or shop. maybe you know a carpenter or an electronics guy. ask them questions. these are invaluable resources to you. they might be able to suggest a faster or better way of doing something for you.