Hey man you did great for your first time those are some nice size good looking nugs.
And for more yield you just got to LST and top the plant a bit, try to fill out your whole tent with a even canopy. But also make sure to leave some room between each cola, you don't want your plants to be cramped.
My first grow I harvested too early and had garbage ass weed. My plants were cramped also, so the lower nugs were really small even for harvesting early.