I stumbled across another great thread on BGG by Tom Vasel of The Dice Tower fame.
This thread is the second part of Tom's collected wisdom on board games design. Tom's been around the block asking an impressive list of game designers, publishers and reviewers for their advice to aspiring designers. The results are definitely worth a read, they'll repay the time spent reading them many times over.
The first part of the advice is available on The Dice Tower's website.