Neocron is a quite complex game, I recommend techhaven.org and their wiki for help.
As for what to do? Focus on combat skills, you level faster if you put most of your points into them to start. you should be outlevelling gear so fast that you can ignore repairing for the most part.
Find some sewers, take a weapon of your choice in and go to town!
Also, take some recycling skill and use that to make your own ammo! put the recycling tool in slot-1 of the processor, the ammo in slot 2 and fill the rest with junk from your kills (limbs and whatnot), and you can clone more! saves a ton of cash.