So i'll start
To beat the first 3 of the ginyu force i usually used the same combo.
Punching 4 times then pressing d. This will throw the enemy back, and fire at them doing fairly around 100 damage for the ki part while the first 4 punches probably does 130-250.
Of course once you use that hold s down taking less damage then use possibly kamehameha, and super cannon.
If you get low on ki run away, and when their off screen press a, and when they get back on screen run until they get off screen again.