How should I have evaluated the number of outs in this hand

I was in a pretty loose 1-2 game. I was there for only about 30 minutes so I couldn't say much about villain. My hand met the calling criteria so I called. The flop gave me an open ended straight draw albiet the low end and a flush draw. I considered this a big draw and decided to play it the same way I would play a set. It turned out I was drawing completely dead. I don't want to be results oriented but after reflecting on this hand I should have significantly discounted my outs. Please go over how I would properly approach discounting outs in a hand like this one.