There are a lot of stats you can use like the gaming history of the players but in the end, it is gambling. Some people ignore those stats because the team if their favorite. Some bet on this specific team because they think the team has stronger line up than their opponent. Esports betting is difficult because either team could "comeback" and take the lead any time during the game.
What you say is similar to any other sports betting. You do analysis on the team, think about environmental factors that could change the outcome and see what condition the team mentality is before you place a bet. Or some people like to get a tip from the bookies as a small investment on what fixing may be occuring in the game.
Esports are not free from cheating/fixed matches. You have to be lucky here or you will lose a lot of money betting on the team which you thought would win but was a bluff.