I like to go over a few interactive quizzes on Pokercoaching.com (I am not paid to sat that, lol) and review the GTO charts for the type of game I am going to play.
Ask myself 'am I in a good frame of mind today?, Is there anything going on in my life that may cause me to be on tilt? If i'm not in a rested positive midframe i am probably making a mistake playing.
What can I do before sitting down to poker? I personally work, look through the information I am interested in, and only then I sit down and play poker, well, not always, but mostly.
I make sure that i am in a good mood and have a clear mind before starting to grind poker.
15-20 minutes meditation or some simple yoga poses can boost your mood and calm your mind. While playing i like to listen to relaxing music. Dont forget to open the window between the 5min breaks and let fresh air in. Helps to avoid getting headache and tiredness.
I dont do anything special in particular,i just watch a movie or something.Sometimes i play some play money cash games to kind of get the feel for the game before playing seriously.
I don't really have any rituals that I do before playing poker. The only thing that I really do is get to a place where I can concentrate and shuffle up and deal!