I just go with my instinct, I don't hold back the thought if I had a feeling that this game might be this one or that one.
You are right, 99 percent of the time it's always based on instincts, even after making your research you still have to trust your instincts. Gambling is mostly about luck because after doing all the statistical analysis you might still end up losing. Having to do all those work takes the fun out of the game, if you have to calculate and do all those brainstorming before making a bet it no longer becomes entertaining. But instincts are just feelings and they might just push you into making the wrong decisions, so I wouldn't say that you should always rely on instincts everytime, keep it balanced, have knowledge on the games and sometimes go with instincts.
Knowing the game you are playing is very important because that would help you make sound decisions and have good analytical statistics on whose favor you should bet on. Sometimes, your analysis can work out perfectly well and in some cases, it turns out the other way around which is normal. One thing we should know is that gambling is a game of luck, one either wins or loses, If you feel convinced by your instincts based on what you have played to work for you then so be it but if you feel disturbed even when trying to bet on it, then you should know that you are not stable and should implore your analytical strategy to help you out but do not put your hope in it as gambling is all for fun.
Indeed, even how good is your research it will not serve as guarantee that you will always win, though it gives confidence with your decision and it serves you decent trust to wait for the outcome, it's instinct that resides inside as basis, either past experienced or knowing that there's a good advantage for the team that you pick for your bet.
It's important that you know what team or players to pick it lessen the fear though it's mostly luck that brings the win.