[thiagofm]

Don't waste time with design: use twitter bootstrap, jquery UI and stuff that let's you do it later.

Know the ins and out's of auth and stuff that most of web app does have.

Know what the hell you are building -- development/programming is impossible to master so you will spend most of your time googling shit and fixing errors, try to minimize the amount of time spent.

Know how to emacs/vim/any text editor that makes you productive.

Know how to deploy fucking fast.