Help for those building their own interfaces

I just wanted to start this thread for anyone that is having problems building an interface or afraid to try it themselves. I have considerable experience in building them and I'm confident I've made every possible error in building them so I feel I can provide a lot of help to those having the same problems I did. The main problems seem to be with the transistors and more importantly, their pin orientation. It's hard to see the tiny part numbers on them and easy to solder them in the wrong way. I have tons of information on the many different transistors most people will run into and will be glad to give advice as to which way they go. I started mapping the orientation of each transistor I successfully use to build interfaces. I use this as a quick reference guide when building them myself. If anyone needs help, just post a message here and I'll do all I can. Good Luck.