A clear mind makes for clear playing
The most common advice I give to all my students is to RELAX and BREATHE.
Breathing properly is such a key element to universally all activities. Think about boxing someone, or lifting weights, or running a long distance, or meditating. All these share a strong bond of needing focused breathing, not to mention the physical components. Drumming fits right in this category as well. Breathing and staying relaxed while playing is just as important as the physical mechanics, both completely intertwined.
Breathing and being relaxed while playing can be learned just like rudiments and beats can be learned. They both require practice and repetition. So I tell my students to add it into their mental checklist. As a beginner, you're probably concentrating hard on keeping the tempo, moving between different beats, maybe some fills, but try to always include breathing and keeping the body relaxed in that mental checklist, it's a good habit to create.
I know it's already hard enough just to play, before even considering how you're breathing, I hear it all the time from all my students. I get it, believe me. However it should always stay on the main mental list, just like keeping tempo. Tensing up affects all aspects of playing and can become painfully obvious in the sound. Not only that, it'll destroy any stamina you have quickly. The good news is it becomes easier and easier with practice. Give it the attention it deserves.
Mushin - The mind of no mind
Getting your breathing steady without tensing up is a giant leap toward getting into a good flow state overall, where playing becomes fluid and seamless. There is a Japanese concept called Mushin, the literal translation, "no mind". The key idea of not cluttering your mind with thoughts and emotions, so to allow the freest focus without distractions.
Mushin was a big part of Samurai training. When a Samurai warrior encountered another, it was pivotal they stay aware of their surroundings and able to quickly react without hesitation, relying fully on their past trainings and instincts. Over time, it became a key fundamental of many martial arts, for the same reasons.
On a less deadly level, drumming shares a similar headspace. For me, this is the holy grail in terms of mindset with playing drums, particularly when you're jamming with other musicians. The ability to take in a lot of sounds, process them, and react musically in real time is not easy. Distractions from day to day life can clutter up your thoughts and severely effect your playing. For instance, if I'm having a bad day and then have a rehearsal that night, my playing can really suffer just because my mind is preoccupied with work, relationships, money, whatever. I try to keep as much stress as I can at the door (mentally) before I sit down to play music. The outcome is night and day for me, and I imagine the same for everyone else.
- Closing thought -
Being relaxed both physically and mentally are key ingredients to successful drumming. These take practice just like learning about stick control, coordination, and groove. It is one of the main secret sauces to reaching your next level. Use the idea of Mushin as the target and build that into your practice routine.