....If frying them is best, then perhaps there is somewhere on the site that tells you how to do this without burning them....
Hi After8,
Frying spices is essential to:
a) remove the "rawness/bitterness" associated with uncooked spices
b) release the "essential oils" in the spices (and thereby release their flavour)
Frying the spices (whether whole or ground) is invariably done at the beginning of cooking....i.e. after cooking any garlic, onions and ginger.....and prior to adding any meat/curry base/vegetables, etc (at least this is how I do it

).
However, some spices (e.g. garam masala) are generally added towards the end of cooking without frying.
If anything, I would air on the side of caution and undercook the spices. As CK suggests, if you burn the spices, ditch them and start again, because they will be bitter and ruin your curry.
Personally, I generally add water to powdered spices to make a thickish paste (of similar consistency to tomato puree). This reduces the chance of them burning during frying. They are cooked when oil rises to the surface (the "bhoona" process).
Alternatively, if you add the powdered spices directly (i.e without making a paste with water), add just enough water (no more than about 1/4 of a cup or so), a little at a time, after about 10 seconds, or so, to stop the spices from sticking and burning.
If I fry whole spices, I fry them (the "bargar" process) for about 20 seconds or so (until they just begin to change colour...no more), before adding the paste of powdered spices.
In my opinion, never skimp on the oil. A reasonable quantity is essential to adequately cook the spices and distribute the flavours throughout the curry.......any excess oil can be removed prior to serving.....just my opinion of course

Hope this helps.
Regards,