First of all, keep your shutter speed up! Be aware of it, watch it, think about it. Make choices that allow you to use a higher shutter speed.
And of course if you have a viewfinder, use it. Keeping the camera at your eye allows you to keep your elbows in and your body in a line. Shooting at arm's length is much less stable.
Then, experiment and practice.
Experiment with how you hold the camera and lens. Other than what is required for safety, there is no one correct way to hold any combination. Figure out what is best for you and your body.
Relax. Hold firmly but not tightly. Every bit of tension in your body will communicate itself directly to your lens. Stay compact. Keep your elbows in.
Learn to control your breathing. This takes a lot of practice, but eventually becomes automatic. I was taught to fill my lungs halfway, pause for an instant and relax fully, then hold my breath and press the shutter. This has always worked well for me. If I take a deep breath and then hold my breath, it adds tension.