The easiest tip that I can give you is you need to put yourself on players place so that you can understand them more. You have to be a player of the game you want to bet a money and watch how the players play the game then think about them. With that thinking, you can easily identify who is the strongest but you cannot tell the accurate prediction since DOTA 2 is a team play and team work can easily torn apart if they have an issue with each one.