Many factors can affect connectivity, some would be game mode, what times you are playing, and as Falcon has stated, location.
As stated, gamer density around your area may be low, and hinder your ability to find a match.
We recommend playing during peak hours, which if often after school/ work hours until 10-11 pm. Since more players would be available, it can improve your chances of finding a match. Same would apply to the game mode you are playing. Selecting a popular game mode, would have the same affect when more players are available.
Other options you can look into would be to play on a wired connection, set a static ip address for your PC, and set up a port configuration to optimize your connection. You can check out Falcon's Guide on how to Achieve an Open NAT.