Well, like you, I've only had 3 fights, but I've had 3 wins! But anyways, you definitely need to be more aggresive if that's what'll work for ya. When I fight I like to lash out with a lot of jabs. And his guard was way low at a lot of parts, and it didn't seem for any strategic reason, you could have landed a lot more sucessful shots if you wanted to. Since your opponent didn't seem too aggresive either, you could have landed some hooks to the body for points, Also do some 1-2s. I find hooks to the bodies and 1-2s are the easiest way to get points. Also snap your jab more, you seem to be pulling back slowly just using your arm at parts. And if you are a counterpuncher, I saw like more than 5 spots where you could have easily since your guard was up, and his gaurd was shot. But anyways, good fight, gratz on the win, good luck on your next one.
EDIT: I like to stay flat footed while waiting for my opponent's response, and toes if my opponent is lashing out. It helps me increase my concentration It actually helps me stay stationary, and tires you out less at points if your knees start to shake out of fatigue, toes help me dodge and make your opponent stop his combination. You should try it, but during sparring prefferably. Also ask about doing mitt punching a little faster, my coach at the gym always puts an emphasis on speed of punches and power, so he always increases the pace of his mitt punching drills dramatically which is necessary for amateur boxing. That should help you with lashing out your jabs. He also likes to look for gaps in your guard and punch you wherever there is a gap even if you are shadow boxing hah. It really keeps you tightening you gaurd knowing your coach is like a ninja with punch mitts.