#5 - Chasing profit:
To keep your profit margins high in any business, you'll need to adjust your choice of products frequently to keep up with what's recently profitable. The most important tool you'll ever have in any industry is a spreadsheet or application to calculate build costs for you. By updating the prices on your spreadsheet regularly, you can quickly spot which items are profitable to build and stay ahead of the curve. This is important because in some areas, like the market for Tech 2 modules, it can take as little as a week for an item to go from high profit to making a loss. In EVE's highly competitive markets, it's the most agile players able to stay on top of market trends who make the most ISK. There are several freely available applications and websites that can help with practically every industry but I've always found it useful to make my own spreadsheets.
Skip past the cut for four other invaluable tips on reverse engineering chances, invention profit margins, predicting trends and more.