|Adventures of an EVE Online Newb||
EVE Mentat is a trading tool for Eve. You can view all your wallet transactions, orders and market data in a single location and compare them much more easily across regions. While in EVE, use different characters in different regions and click "Export to file" for each item in the market. Then in EVE Mentat, import the market data from those files. EVE Mentat will tell you if your order prices are unprofitable and it will make it easy to compare which regions have the best buy/sell prices for items.
EVEMon is used for skill planning and making sure your character is training up the skills you need. It helps also because you can tell when you need to login and setup a new skill training queue. It can give you a listing of future skills that you have to train as well.
Python Fitting Assistant is a tool for helping you pick the best items to fit to your ship. It will even factor in your skill levels to give you a more accurate analysis of your ship fittings. Use it with the market data tools to find the best prices for items, and find out which skills you need to train up to get the most out of your ship.