detecting sets

My name is Don and I am an average poker player. I have been very succesful at live games but struggle online. I am not sure on what i am doing wrong but I do know that I need help figuring out how to detect a hidden set. I have lost so much money online becuz i will have AK and get called with pket 4 or some low number and the flop will come A 4 j and a lot of times it will look like a flush draw that they are on. How do you distinct the difference. I play very low limits of no limit poker online. If any one has any help I am in dier need. Thanks
Don

Have wider opening range, than only big pairs and learn about SPR concept.

If your playing low limits I wouldn't be overly concerned.

A classic set line is call flop and c/r turn.

But I wouldn't lay down big hands because they might have a set. Sure, they could have a set but they could be doing the same thing with so many other hands that you beat.

Don't out think yourself and don't lay down big hands for the most part.