Take up rowing or kayaking. Doing a sport that activates your arm muscles will help you to tone your arm muscles. Consider taking up an arm focused hobby like rowing or kayaking, which requires arm strength and good core engagement. You can start by doing the rowing machine at the gym and then work up to taking classes in rowing or kayaking. You can also join a recreational rowing team in your area to get better at rowing and be more active on a weekly basis.
Start the clock, and do as many squats as you can — while maintaining perfect form — for 30 seconds. Then rest for 10 seconds, and do as many single-leg deadlifts as you can (again, with perfect form) for 30 seconds. Stick to one leg with the deadlifts for the full 30 seconds. Then rest for 10 seconds again. Finish up with 30 seconds of glute bridges. Rest for a minute or two, and then start all over again.
Bend your knees to lower down into a split squat. Your left knee should ideally form a 90-degree angle so that your thigh is parallel to the ground, and your right knee is hovering above the floor. (Quick position check: your left foot should be stepped out far enough that you can do this without letting your left knee go past your left toes—if you can't, hop your left foot out a bit farther away from the bench.)
Back to the tricep pushups and really activating those tricep muscles for toned arms. If you need a rest, that's totally cool. Just take a break in the up position and maintain that plank form. This way you are still working your arm muscles just by holding your body weight up. So that's totally fine for some of our beginners out there. For those who are more advanced, we want you going as hard as you can and trying to hit that 15 to 20 reps. You're doing great.