I have a short story about eSports betting.
I have this friend who is into eSports recently, which is a Dota 2 game. Back in the days, where he is only betting with his items on Dota 2 which it has value in US Dollar($).
He is really owning before, he even used his profits on gambling to pay his tuition fees on college.
I asked him how he did it and how he become owning and most of the time is winning with profits.
He answered me, "You need to focus, bet only on those game that you know".
Then I really agree to him since he is also one of the best Dota 2 players in our circle of friends, so no doubt if he knows how to analyze every team and fights in Dota 2.
In short, it much better to bet on what you know, especially in games, eSports or non-eSports.
Nice story about your friend, he's right there's no need to have some sort of special strategy in betting. Since Dota 2 is a game that is between two teams only, you've got the 50% chance of winning already.
But knowing who are the teams and players playing then this is where the odds will start to change. Starting from tier 3 up to tier 1 teams, you can have an idea if you mostly watch their games and replays.