I know how you feel! I got my first horse this year and she is very gentle and sweet, but she was so big that she couldn't feel it when I tried to cue her.
When you are wearing spurs make sure that you have your heels pointed down, but keep your feet parallel to the horse instead of pointing your toes out. Cluck with your tongue and squeeze with your calves while shifting your weight slightly forward. This should make it obvious to him that you want to go forward and will help to keep your feet away from your horse. If he doesn't respond he is most likely confused or just being stubborn
Don't worry about trying to do it right the first time though, it took me a month to get used to it and by then my horse responded well anyway. Also, try looking for some more friendly ones that are blunt and small if you don't have them, because they work better for "tune ups" and to "lighten them up". The bigger and sharper the "quicker the result" but they usually just create problems, so I would go for the smaller.
Good luck to you and great job for working with your horse!!!!