Ramon, I know what you are talking about about spraying and missing. So this is what I have done:
Once I die, I first person spec someone who always hits or gets headshots. I carefully watch their crosshairs as they spray, burst, etc. I note how they pull or sweep side to side, or aim high. Granted, sometimes I see a scout hs that seems like total bs, but that is the nature of the beast. Overall, I can say that first person spec'ing elite players has improved my success. As with all things, be patient grasshopper...