Well s*** i got here late...
Sorry if i repeat some stuff but ill just tell you what i know.
Im 16, 6', and 165lbs. So im in the same boat as you are. On the whole reason why your still small after those years of workoing out, my best guess is cause your body was too busy growing upwards to be able to actually build muscle like you want.
Onto the present, on your workout, like ppl have been saying youve got to much clutter, trim it down to more sets of simpler stuff. You dont need 6 kinds of curls when 2 will do just fine. Also listen to suncloud, mass builders are key, especially squats. On what weight to use, your right that you want to hit the muscle hard so itll grow, i suggest using a weight that will allow you to do 6-8 reps per set, thats what ive heard and so far its working for me.
On the whole fluid thing, alchohol, soda, energy drinks, starbucks, jamba juice(<-- especially stay away from that crap its got like 80+g of sugar per cup) DONT even think about it. Maybe some sugar free stuff occasionally, but i say stay away from those to so you dont pollute your body with the unneeded chemicals.
Water, water, more water, and then some more water. IMHO you need minimum of 2 gallons a day. Your probably thinking "wtf why that much" because just like you need alot more calories for your new muscle, you need alot more water. And you should drink at least a .5gallon b4 bed, just cause your asleep doesn't mean your body doesnt need water. Yes you probably will have to piss alot, but you need the water.
Food. Depending on your metabolism you need alot more food then these other guys. Were still 16 and have high metabolisms. I am at least. Im an ectomorph, so when i get 3.5k calories of food, thats just a normal day, if i dont get at least 3k, ill start loosing weight lol. So im trying to get around 5k calories a day.
Thats right... 5,000 calories a day.
If your an ectomorph(really high metabolism) like me, you may need a whole lot more food.
Lastly, on the whole supp thing. Were 16 stay away from the s*** for now, theres enough crap going on w/ hormones it doesn't need that stuff. Protein shakes are fine depending on whats in them, i say stick to the more natural stuff w/o all the crazy addatives. Im also taking around 10mg of creatine a day 5 prew/o 5 postw/o. Other then that just forget about it, its not gunna help anyways.
so yeah, thats what ive found out, and what im doing so yeah. Hope i helped.