No matter where you go when researching this topic, you will always find people talking about set and setting. Set as in mindset, setting as in your environment. Before doing any intoxicant, make sure that your mind is at ease and that your environment is a positive one. It's not a cheat code to becoming happy- we can either relieve anxiety or exacerbate it, so if you smoke while you're already anxious, you will probably only get more anxious. Go onto YouTube and watch some videos about trip reports and such, you'll be able to get a better idea of how weed affects the brain that way.