Common experience among developers - too much emphasis on making graphics and not enough on scripting. Branches are also another killer - make a poll and ask players whether they want, everyone says the more the merrier. Then the permutations rise and game over.
From the screenshots I would say your graphics are already there, no need to invest too much time improving in your next game. As for the story and dialogue, it remains to be seen what your new game can offer.
As for branches, I would say start off with simple choices that allow players to reject LIs. This might look simple at first, but it can already get challenging by mid game. Doing real meaningful story branches is incredibly hard for an individual developer and not recommended especially if you don't have a few completed games under your belt.