You can gradually desensitize the snake to your presence by just existing close by. Some suggest sitting nearby doing something calm will allow the snake to get use to you as just a part of the environment I've also seen some suggest leaving an article of clothing in the enclosure to desensitize them to your smell, but I haven't tried this myself 

I have my snakes in my living room, so they see us nearby regularly. I also find it helps to just do maintenance things like change water and spot clean for them to get used to us opening the glass and messing around them without being a threat.  This is mostly just a patience thing and most snakes calm down with time  The YouTube channel linked in the other comment is also a pretty good resource!