Best way to get caps?

Started the game again after ages (I feel clueless and noobish) and have completed all missions now. I wanted to buy some mutation recipes but they are really expensive, what is the best ways to collect caps?

I log on daily just to take all items from things I kill just to sell at train station’s, i bulk and sell my junk at train stations, I have a lot of items in my camp for sale but still don’t seem to be getting anywhere. Was wondering if anyone had any quicker ways to get the extra caps in?