I still read/watch professional reviews every once in a while, but I choose to be skeptical about it, and take it all with a pinch of salt. To me, it's not as much about the score, which is usually hyped or unfair, as it is about carefully reading the reviewer's opinion in-depth to try and find out what they really think about the game. Review scores have been wrong for decades, now, to the point a 7/10 or 3/5 game is considered 'bad', when I tend to find those scores to still be pretty good.
It all boils down to personal preference and taste, like it was said before, so try to find a reviewer, professional or not, with whom you are more likely to agree, and read or watch their reviews. Or, like tinyE said, just ask for information on a game here on GOG forums, people usually give good advice in here. When in doubt, just watch some random game play clips of the game (preferably with no commentary) to see the game in motion, and make your own judgement on it.
As of late, I've mostly been buying (and being gifted) indie games, and I think I still have the same attitude towards those titles as I did when I bought games in stores, 15 years ago, which is to trust the screenshots and the box art and go with my gut feeling that 'I'll enjoy it'. So far, it hasn't let me down. AAA games are harder for me to go with gut feelings, because they're more often than not just rehashes of old formulas rinsed and repeated ad nausea, just under a shiny graphical coat of paint.