I only recently started playing poker and tonight i won a freeroll ticket to play for a $150 GGmasters ticket.

I have played almost freeroll on every platform but this one will be something special if i do win. However, i am so nervous i am having sweaty palms! I know it is only a freeroll and nothing to be fuss about but we all start somewhere. I didn't even feel this nervous when i had my first Muay Thai fight!

I don't mean to frustrate you ... but a pro isn't preparing for a $ 150 tournament. his eyes don't flicker ... there's a good chance he'll be playing several high(er)-stakes tournaments at the same time. Relatively many weaker players will also start on the 150 ggmaster. So, don't be afraid ...! good luck!

I am definitely not a pro, but what I like is doing a hand stand before the tournament starts to increase the blood flow to my head.
On a more serious note, I think pros are so used to playing high stakes poker, it's like going to the store for them. Being positive and having a good mood surely helps. Good luck

I recommend you play a session before the tournament to warm up and not make mistakes that we make cold.

Generally pros are preparing by studying the game, working on the mental component, getting in good volume, etc.
In your case I would say don't worry about the outcome, just play your best and have fun. Congrats on winning the freeroll ticket and I hope you win the GGmasters ticket!

The technical component covers all strategic aspects, including learning to push-fold and working with different board textures postflop.
The psychology of poker is the second part of the preparatory work, here it will be useful to analyze the most common causes of changes in the emotional state (inclination); we will cover this topic in a separate article.
The practice is about your physical condition, taking care of your body and brain, getting in better shape to focus and realize your maximum potential over a long period of time.

They 'crack' their knuckles,,,,

I think that a characteristic feature of professionalism is the lack of panic. For professionals, emotion control is paramount. I recommend you go for a walk and breathe fresh air before the tournament. I'm sure it will help you.