Look on the left side of the carburetor.  You'll see a screw with a really big head that you can turn with your fingers.  With the engine warmed and running, turn that a bit.  Turning it tighter (clockwise) will make the engine idle faster.  Of course, too fast an idle will make very slow riding not-so-slow.

About very slow riding.  Do parking lot practice.  Your clutch is made to allow you to part-engage/release/part-engage/release so you can ride very slowly.  It's in oil.  Practice riding as very slowly as possible in an empty parking lot.  Ride straight slightly engaging your clutch for a momenht for a bit of speed, then squeeze the clutch lever to coast very slowly.  When you can do this straight, make very slow turns.  Make them as big as you need.  After you get your balance improved, make the turns tighter.  Here's more about the Friction Zone of your clutch.  Here's a very good routine for parking lot practice.

Quote:
Never, ever panic.  Always know what you want to do, where you can go, and do your best to accomplish those.  

LOOK at where you need to go, NOT AT THE PROBLEM; see that in your peripheral vision.    You'll drive where you're looking.

You MUST slow as needed before entering a turn.  Go deep into the turn, THEN TURN.  Do not start a turn early.  Slow as needed, go deep, turn somewhat sharply, smoothly roll-on the throttle gently*, and straighten as you come out of the turn.  Try to never need to brake in the turn.  If you are running wide push harder on the inside handlebar and lean your body into the turn (to lean the bike less and try to avoid dragging the pegs).  Here's More.  If you need to turn AND panic brake, you're in deep trouble.  Panic brake only when straight and upright.  If you need to panic brake while turning, keep your mouth shut to keep the gravel out.

*Too much throttle while turning will make you run wide.  Just a bit of roll-on adds stability in the turn.  Cutting the throttle in the turn makes the bike turn tighter, but you should'a planned for this in advance, got your speed down, turned tighter to start, and rolled-on the throttle as the turn progressed.