I've tried to avoid playing absolute crap when it came to the NES. I've rented some major duds, I've bought a few minor duds...
...but there were a number of games I stayed away from just because I knew it was bad. I think it was partial thanks to game magazines EGM, Gamepro, & Video Games/Computer Entertainment magazine based their reviews and it's how I based my opinion. In '87 & '88, all I had to really rely on was "Nintendo Fun Club" news... and most games you could count on first party Nintendo to be good.
...back in those days, however... you had to buy the game, play it, and if you didn't like it... could return it to the store (before they had game rentals). They kinda got suspicious after returning 4 games in 2 days.