2) Buy pieces that can work for more than one season. Of course this does not mean to skip on buying a coat if you live in New York, but keep in mind that some items have a couple-months-only-a-year lifespan. This is also a great tip on picking a color of an item. If a top comes in 10 different colors and it is SO hard to pick just one, picking the neutral one (beige, black, white, etc.) is a great option. Neutral colors transition easily throughout the year...and throughout the trends.
Some great jewelry pieces that I have worn season after season: