story or skit
past present future or dynamic
you don't need to answer here but don't spread yourself thin either. if you aiming at horror then drop romance drama and comedy from the outset. likewise for the others. a good joke every once in a while lightens mood, but your comic might be once weekly, so lightening the mood is just killing it.
don't blow your good stuff on the first comic. if your new at anything and are asking for advice already then the ideas your building now...especially if you think these are the big guns your designing, should be worked on later. do something else first that you'll happily see fail or succeed. good or bad results are valuable because you will learn from them.
don't assume that some basic skills in lirtaracy and drawing will make for a good webcomic. study everything. even if you don't like it, read it anyway. learn from the mistakes of others and build on the success of others.
i'm sure i could think of other stuff, but you probably didn't like some of what i've said so far either.
all my advice is from practical experience learning the necesary skills to get into world design for video games, i have been learning since 2005 and i still have a long way to go yet. i realise the job market for such a position is very tight as world design is by far the easiest of the 3d arts. so i'm currently forced to create my own games. hopefully one day i'll be able to earn one of those hard to get positions.