How do you properly toast rice?
Considering the results you're getting with medium or high heat, I would suggest you try low heat.  If it skips past the stage you're looking for, it's probably cooking much too quickly - you might occasionally take it off the heat as well, to further draw out the window of when you can find it to be just toasted, not burnt.

In addition, look for other indicators of when it's done.  If there's a time component in whatever recipe you're using, (ie, the recipe says toast 6 min) try keeping to it, even if it doesn't look golden brown yet.  Maybe keep checking throughout for that nutty scent, and pull it off the heat when you do find it.  Some foods keep cooking for a while after they're off the heat, and I'm not sure how 'brown' toasted rice can be expected to look (one of the recipes I saw mentioned "pearly rather than browned").  If the color is paler when 'done' than you're expecting, it will be very easy to overshoot.

Depending on what recipes you're using it for, you might try using rice that has been toasted for only a few minutes, see how it affects your recipe, and working your way up the amount of time you're toasting it for to get the results you want - after all, under-toasted rice should still be usable, while over-toasted sounds unpleasant.