Im trying to build muscle on my arms?

Im a skinny guy not scrawny but decent skinny. I really want to build up my biceps and chest and triceps. I work out with as much weight as ican to complete at least three sets reps of ten. I see that i can work with less weight and do more reps and when i work with a little more weight i do less which way would i benefit and see results from in a short period of time?. the weight im workin with is pretty light so how long should i be resting inbetween my sets and reps?? also is there some kind of supplement i can take to build strength without gaining weight and lookin fat?? Ido interval running everyother dayI really want myarms to grow can someone with experience help me in this help me??? appreciate it..