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?
You probably are the kond of person who wants things organized, neat and tidy. For me, i don't usually have much time arranging ledgers and spreadsheets. I seldom even look into an app i downloaded for this specific purpose. I just check real quick the history of my trades through the exchange site itself where i'm trading