On the left side of your head, you’d blow dry (or curl or straighten) your hair at the roots going up and over to the right side, instead of straight down. Then when it lays normally, it will have extra lift at the roots.
Using the thin stick edge, push that into the teasing and pull it forward towards the crown/front of your head. This will give you a bit more lift without you having to tease hair that already has been teased and has product on it.
Clip-in extensions are the fastest way to get instant volume and/or longer hair. Most celebrities and IG gals are wearing them. When blended correctly, they’ll just look like your own hair.
If you need an instant boost, flip your head and hair over, shaking it and scrunching your fingers at the roots. Flip your hair back over and into place.