Firstly, there are more than one route to all objectives.

Secondly, there are things you can use such as flash bang when go around well known sniping corners.

Thirdly, you don’t have to peak around corner especially if you know someone is there, do a side step while jumping out into the corner and ready to shoot back.

Counter Strike is not really a “run and gun” game like CoD is, you can implement a lot more tactics into it to make up for the lack of reflex.