* Develop a good eye for hype and real trends. Try to follow the real trends and avoid the hype-fests. Avoid investing time learning fly-by-night technologies, but when something new and genuinely better comes along, jump on it.
* Listen to developers who have deep and abiding hatred for some technology that they can argue coherently (with a range of deep technical details, links to bug trackers, etc.). These rants are a gold mine can save you a universe of pain.
* Almost all good coding boils down to three things - choosing a less powerful language/approach, writing less code to do the same thing and looser coupling.
* All things being equal, take the job with the higher pay. It almost always means you're treated better in other ways, you work with better people, you work with better tech and on better code.