What youāre going to do depends on your ability level and creativity. At your level, stick to the basics. And donāt go all out (speed and/or power) yet. Itās about progression.
Start out doing the basic strikes you learned in class. If you do specific combos in class, do them on the bag. Basically, replicate what you do in class.
I like to do my basics hand techniques and combos we do in line drills against the air as warmups in class on my bag. Thatāll look something like this (all without footwork):
20 lunge punches (lead hand straight punch)
- High, middle, then low, focusing on technique and targeting, not speed or power
20 reverse punches (back hand, straight punches)
- Same as above
Do the rest of your hand strikes - closed fist strikes like the different hammer fists, open hand like knife hand, ridge hand, etc. *I definitely wouldnāt do spear hand/fingertip strikes, but thatās just me. If I do them, itās just tapping the bag cautiously*
Then Iāll start doing movement in a fighting stance without throwing anything. Iāll slide in, slide out while keeping my hands in fighting stance. Iāll angle left, angle right, circle left, circle right, slide straight left and right. Iāll do a set number of each on each side.
After that, Iāll combine the movements and hands. Slide in, jab (lunge punch), slide out. 20 times or so. Then the same thing, only reverse punch. Then angle in and out, circle in and out, etc.
Then do kicks, the same day or on opposite days. All the same principles apply. Front leg kicks, back leg kicks. Without movement and with movement.
Then start adding combinations - punching, kicking, and kicking and punching together. If you do combinations in class, do them on the bag. Make up your own and see how well they flow.
Pay attention to your form more than anything else. Once youāve been at it for a little while, start adding power and speed. Regardless of how fast or hard youāre hitting, form is most important. Ever see the actual cardio kickboxing crowd in class, is not commercials? Their form sucks. Thatās not really the focus of their training, so you canāt hold it against them. But if you train like them, youāre MA training will look like them too. The point is to enhance your MA training, not derail it.
Final thought - video yourself. Coachās Eye is a great app. You can slow motion, fast forward, rewind, etc. Video will show you what you canāt see on your own.