Jobs
In Freelancer you have the possibility to get your money in very different ways. You can get you money (legal) by trading, by being a bounty hunter, by mining, but also by being a criminal, so pirat, smuggler or terrorist.
Trader/Miner
As trader you earn your money by buying goods inexpensive and selling them expensive. Normally traders fly a freighter, because fighters have more limited cargo hold. Traders usually evade battles, because the security of their ship and of their goods is more important to them than fighting. When playing in MP, you should always order a escort of fighters. Purchase prices should never be higher than average, and you should only buy goods, when you're sure that you can sell them with a good yield. The most important tool of a trader is the trading menu, it lists the purchase and sales prices of all the goods, so that you can always look, where you can get goods cheapest and where you can get the highest yield. But the way you have to go should always be in a ratio to the yield, so it doesn't make sense to fly through the whole galaxy for 15,000 credits. On top of that you should always be aware that several goods could be perishable or instable, and so you can experience big losses, if you aren't fast enough at your destination.
Miners are specialised on gathering resources. They fly to mineable ares on the map and shoot carefully on the little asteroids (the ones where the cross hairs light up). Several of them drop goods like water or metal, which can be transferred into the cargo hold by pressin . This work is exhausting and you don't get much money. You can get more money by transferring all the goods of beaten ships into the cargo hold.
Bounty Hunter
As bounty hunter you accept different missions from groups and corporations, e.g. you must destroy stations or ships, arrest criminals (or enemies if you're a criminal) or re-get objects. Of course you need a good ship with good weapons and shields and lots of nanobots and shield batteries for that. The enemies are, depending on the system in which you are, less or more difficult, the payment depends difficulty of the enemies. So if you have finished the story, it doesn't make sense to accept missions in Liberty, because you get much less credits for the missions than for the ones in Rheinland, for example. So always compare the difficulty with the payment and accept only the well-paid missions you can really do. After each battle you should transfer all the objects into your cargo hold in order to get money.
Pirates - Smugglers - Terrorists
The Metamorphosis
In order to become a pirate simply attack the enemies of the pirates, e.g. the Liberty Navy. But if you don't do that smart, you'll uncontrolled become an enemy of all parties. To avoid this catastrophe, go to Manhatten and fly to the north asteroid field. Bring down as much ships of the Xenos as you can. The Xenos are big enemies of the Outcasts and the Liberty Rogues, but the police doesn't pay further attention to them. So you can easily advance your reputation with the pirates without getting into trouble with the police. But now don't attack ships of pirates or accept missions of the "good" parties, because your good reputation with the "bad" parties would be lost then. You should go for the pirates as soon as possible, because if you don't, it will need more and more time and get more difficult to get a good reputation with them. As soon as you have a good reputation with the pirates, fly south to the badlands. Look for the hidden pirate stations there. You can dock there now and accept rides as well as buy new equipment.
First Action As Pirate
First you should buy good equipment for your ship, then you can start with first assaults on little transports and their escorts. Stay near the Junkers' bases first to repair your ship and buy new equipment there. As long as your adversaries are neutral, you should scan them before you attack them to find out the ones with the best goods without getting too much enemies. With the gathered goods you make money and you get better and better equipment. As long as you don't own the best ship, you should only attack the freighters with the highest profit, the others will start hating you early enough. But this procedure doesn't make sense if you have already enemies in the system, because you will be atacked immediately anyway then. As pirate you should always stay away from common tradelanes and jumpgates, because you will only get attacked there. Move hidden in nebulas and use the hidden jumpholes in these nebulas. Look abrasively for hidden stations and jumpholes, because later on you won't be able to dock with the other stations. In the beginning you get the best missions as Liberty Rogue against the Bounty Hunters.
Smuggler - Pirate
Even on the "bad" side there are two different ways of playing. As pirate you attack as desribed above freighters and execute the pirate-missions. As smuggler you trade with illegal goods, which you can buy in pirates' bases. You can't do both at the same time very good. If you decide for fighter as ship, any trading doesn't make sense because your cargo hold is too small. The same thing if you own a freighter: It has a string armor and many turrets, but you can't do effective attacks with it because it's too slow. It can be possible at the beginning, but at least when the whole Liberty Navy is hostile, you have to fly fast attacks and disappear afterwards as fast as you came, before the number of enemies is too big.
The Omicron Alpha System
This is the best place for a pirate's life. Here are the best missions with the biggest yields. The best missions you can fly are by the Outcats against the Bounty Hunters. As a pirate you really must visit this system. In general a pirate should always stay hidden and never go into big publicity. You should, no matter in which system you are, stay away from big planets and station as well as tradelanes, on top of that you should stay near asteroid fields and nebulas.
And Everything Gets Red
Soon you'll recognise that polices like the Liberty Navy and several other organisations see you as an enemy. And the longer you play, the more enemies will be there. But don't panic, the ratio of friends and enemies will nearly stay at the same, because all the organisations have their enemies, and they will be happy, if you bring down some of them. If you stay hidden and remember the tips mentioned above, you shouldn't run into trouble. But at the beginning of your pirate career, you shouldn't jump the gun on everything and attack everyone following the thought "all of them will be hostile soon anyway". You should think of your bad equipment at the beginning first and do one step after the other. You should also try to keep the numbers of hostiles as low as possible.
Multiplayer-Pirates
In MP you can become a pirate the same way. But don't panic if other players are shown as hostiles without any actions of yours. That are the players who accept missions, e.g. for the Liberty Navy and see pirates as hostiles. Players who live as pirates are shown as friends, as well. Together you can also plan and execute attacks on other players and organisations then.
You want to become "good" again?
Then simply bring down the pirates' ships (Xenos works best). But it can need some time until you are friendly with the police or the Liberty Navy again.