I personally use a spreadsheet but I'm sure there are better way to do it.
Do you know any good websites/apps to do it?
I also use spreadsheet to keep track of my wins/losses so that I can evaluate myself if I have progress in trading and to see also the coins that I profit the most. I don't know any sites or apps just Excel and update it from time to time. I also put in there how many days I hold the coin and sold it. I just like analyzing things.