how do people make hundreds of millions in elite?

Iv got about 500 hours logged and a decently engineered fer de lance for combat and a engineered krait phantom for exploration so I'm not super new to the game but it seems like combat missions only pay a few million each and they can take awhile sometimes and I know the road to riches method but It doesn't seem like people are getting andoconas and fleet carriers by doing these types of things so I was just wondering if anyone had any advice on what they did to make a good amount of money, currently I only have a few ships and 30m to my name. Iv done very little odyssey content, me and a friend of mine tried it out when it launched but he stopped playing and I took a break and just recently came back. Obviously I'm not looking to make a bil a day but more so I'm just curious what other activities I could do besides combat, trading and exploration to make a decent living