If you ever get the urge to see how you're doing over time and compared to the other players in the game, look at the Graph History. Either the tiny one in the corner of the map window or the big separate window you can get from the Window menu.
The first four items in the graph, money, metal, savings, and ship power, just show how you've been doing in those areas over the life of the game. ("Ship Power" is how big and tough your fleets are. It's the sum of all the tech levels of all your ships. It can give you an indication of how powerful your fleets are.)
The last 6 items show comparisons between you and the other players in the game on a turn-by-turn basis. Rank is income rank. You'll find that if you have the highest income turn after turn, you'll probably do pretty well in the game. The other 5 items are your relative technology ranks; you will find that if you fall too far behind technologically that no amount of money will probably save you from overwhelming enemy forces.
You can turn on and off the various graphed items with the icons at the bottom of the graph.