Differentiating between 收 and 受
You may see the definitions of these two characters on zdic.net (maybe you already know), an online dictionary which is convenient for looking up the characters.

As a native speaker, I think (subjectively) the main difference of these two characters is that 收 emphasizes the action of receiving, gathering or reducing, and 受 emphasizes the finish of receiving an action, which is something sort of similar to the perfect tense.

I guess that your doubt comes from distinguishing 接收 from 接受? In some sentenses these two words are almost the same, for example:


  他接受了这份礼物。
  他接收了这份礼物。


But I still feel that there is a tiny differece as I said above, 接收 puts more significance on the action of receiving.

Another differece may be that, 收 is usually used with "concrete" things like gift, data, signal, while 受 is usually used with abstract things like suggestion, training, offer, and only some "concrete" things.

Hope it helps.

Reference

收 on zdic.net
www.zdic.net/z/1a/js/6536.htm

受 on zdic.net
www.zdic.net/z/16/js/53D7.htm