Practice, practice, practice! Find a good parking lot and use the lines to practice on your U-turns. Feather the clutch in the friction zone and pressure on the rear brake to stabilize the bike. Most important is to turn your head and look where you want the bike to go. Amazingly the bike tends to travel where you are looking. Don't cheat by only moving your eyes, turn your head.
A big advantage of fuel injected bikes for slow running is that the system will keep the engine at steady rpms as the load changes, within limits. You can just leave the engine idling and use the clutch for your speed control. Lightly dragging the rear brake is also a help. When turning, a sliver more clutch will tend to stand the bike up, and a sliver less will let the bike drop into a sharper turn. Try slow running in both 1st gear and 2nd gear. Some riders prefer one, some the other.
Find an empty safe parking lot with the parking spot lines painted at right angles, not diagonal parking. First ride on the straight line. Go slow, then slower, slow, slower, slow, slower, slow, really slow, slower, really slow, slower, really slow, etc. until you feel smooth at it. One or two good rides is not enough. A dozen is a good start and not enough. Change to turns. Make circles on the lines, maybe 4 lines across (often 8-1/2' or 9' wide per slot). Circle left several times emphasizing the full head turn to look where you need to go, and be comfortable and flexible on the bike--no tight muscles anywhere. Circle the other way. Slowly and smoothly. Don't be surprised if turns one way feel smoother than turns the other--that's common. Now do circles 3 lines across. Scooting your butt over on the seat to the outside of the turn so the bike is canted into the turn helps at slow speeds. If that size circle is difficult, use 3-1/2 lines across. Make several circles, then reverse direction. Now 3. Now 2-1/2. Do figure-8's on those lines, start with 4 slots. Emphasize the head turn. Scoot across the seat for each direction if you're comfortable doing that. Now do figure-8's 3-1/2 slots wide. Now 3 slots. Now 2-1/2.
Repeat tomorrow. And next weekend. And the next and the next. Perfect practice makes perfect. Don't try to progress faster than your balance develops.
On the street at higher speeds you need to shift your butt across the seat the other direction, i. e
., toward the direction of the turn so you lean toward the pavement. But, take one thing at a time.