I wouldn't worry about the Scout base upgrades for now. Basically it will be cheaper to find better equipment at this early stage. Learn how to use the search function - it is definitely your friend. With your first ship, you need to trade in the crappy equipment you start off with for better and smaller stuff. The size is VERY important. Ideally you want most or all of your equipment to be size 20 or below. No size 60 grippers.
Once you have done a couple of quests and gotten some smaller equipment, you should have at least 100 free space on your ship. This means you can start making a profit from trading goods. I don't generally find it too useful to deliberately go to a system for trading per se, but I always make sure to have a look at what's on offer in every system I visit. I only buy things that have three 'thumbs up' signs in the buy column (you'll see what I mean). Be warned that you can't buy weapons or drugs without a big negative effect on your reputation, so I wouldn't bother. But equipment, medicine and sometimes luxuries are good bets. I don't use trade a hell of a lot, but it can get you going financially early on.
Other marginal activities for money including picking up minerals from asteroids (which hardly nets you any profit) or buying research probes to mine empty planets. This is okay, but still isn't that spectacular. Ultimately, in SR2 you will make your money from two main sources: quests, and selling Dominator parts.
QUESTS
At the beginning of the game, you are much too weak to successfully destroy pretty much anything. You are also too slow to stop enemies from landing on planets or otherwise getting away. So you definitely want to steer clear of anything where you need to destroy any ships. Ship escort missions aren't that much better, because the routine pirates will be far too strong for you. The only thing I'll say here is that there's no requirement to actually escort the ship you are supposed to be defending. It only has to survive until the specified date. So you can sometimes win these quests without lifting a finger. But it's risky.
Some people hate the real time strategy battles, but I quite enjoy them, and they are quite easy for most of the game. They also ramp up in reward quickly. So I would recommend learning how to win these RTS battles. I can write more on this topic if required. The easiest type of quests are probably the 'fed-ex' type (in which you must deliver something somewhere, and sometimes return too). The key to succeeding here is not so much engine speed but JUMP RANGE. At the beginning, you will have a jump range of 18-20. This is bad, because you will need to make several small jumps to reach a specific system. Time is taken up, not by the jumps themselves, but the intra-stellar travel (i.e. within a system). This sucks, because you will normally need to re-fuel every time you make a jump (unless you have a big fuel tank, of course). So you need an engine with a bigger jump range, and a bigger fuel tank. In my current game (which I've only just started) I was lucky enough to find a micromodule which when put on the engine increases jump distance by 8. So now I can perform jumps of 30 parsecs or whatever it is, and reach the destination system in less jumps. This translates into a much higher chance of completing fed-ex quests on time.
Then there are the text adventures. These are great and I highly recommend giving them a try whenever you get the chance.
DOMINATORS
Later in the game, you will spend a lot of time fighting the Dominators who have taken over a sizable chunk of the galaxy. You will also find that several systems are routinely attacked by the Dominators. But of course the Doms will own you if you try to attack them. One great money spinner, however, is to lurk around Dominator fights hoping to pick up the equipment they drop when they blow up. This stuff is VERY valuable. The nodes are less important, but you can pick them up too if you want. It takes a bit of experience to know when the coalition forces are going to win a fight against the Dominators, and in truth I still need to quickload a bit when trying this, but if you pull it off you can score some great stuff. The stuff can be sold in the normal fashion, or even better, at scientific stations. They pay top dollar in the name of Dominator research, and this contributes toward winning the game as well.