Isn't it clear? Experienced developer can give you huge list what to do and why, and what not to do and yet again exactly why. I'm seen millions of ways writing extremely bad and unreliable code. I can tell exactly why not to write such code. Nothing kills more productivity than totally unreliable code. Use transactions, locking, handle exceptions, give clear error indicaton, log possible issues. Use auto-recovery, if possible. It's not that hard, it should be really obvious for anyone. Don't write stuff that totally kills performance, use batching, sane SQL queries, indexes, etc.