I started off by mining..then somehow veered off the story and just explored randomly. I tried fully exploring one system at a time and kept doing jobs within a system. Pick missions you're comfortable with and pick the right ship and weapon that fits your style. I tend to like fast maneuverable ships. I like long range, slow firing sniper weapons for my playing style. Also, eventually when you have enough money, it's not a bad idea to hire mercenaries for missions you have trouble with. I finally was able to beat this one difficult planet with the help of 3 wingmen.
I finally beat the game 1-2 days ago after ~15 hours. Most of those hours were just messing around...but I ended up with the most expensive ship I found so far. I think at one point I had 3-4 million saved up.