If you want to exclude a whole website from your google search, you can achieve this by adding -site:yourwebsite.com to your search.
For example, if you want to find a download link for a software, you can exclude the website chip.de. I use this example because they began to install annoying adware with their “download manager”, that has to be used for some time now instead of a direct download of the file you want to have.
For better usability you can also save a link in your bookmarks that sums up some sites you do not want to see in your search:
Let me know, if you found a besser possibility that works for you.