One thing I really hated when I was new was forgetting to shift all the way down to 1st when stopping. Let’s say I stopped in 4th gear. The light turned green and traffic started to move. Let out the clutch and the bike stalled. OK, shifted down one gear (to 3rd), let out the clutch and the bike stalled again. You get the picture – wasn’t pretty.
Also, when stationary, the bike often doesn’t want to shift down. Like eternal noted, let out the clutch and barely get into friction zone and click down one gear, without moving, pull in the clutch, then let it out and barely get into friction zone and cilck down another gear, and so on, until you find 1st. When stopped, by getting into the friction zone, or by rocking the bike forward/backward a few inches, you line something up (forgot what it’s called – the synchromesh?) in the transmission to make shifting possible.