I don't think you have a lot of room to criticize people who make vulgar or low-brow comics.
Anyway, here's my advice.
Your political comics are often too specific. Even people who share your political views may find it off-putting that you basically tell them what to think, as with the "Republicans are so screwed-up" line in this one:
[Click to view comic: 'The Road Less Traveled']
I do like the "no one has given you your opinion yet" line. But this comic would be better if you just omitted the last dialogue bubble entirely. Just show the reader some Republicans acting screwed up, and let them draw their own conclusions.
Doonesbury is, IMO, perhaps the only decent political comic: never annoyingly preachy, and always at least a little bit funny. I don't know whether you agree with Trudeau's views, but you could probably learn a lot from his writing style.
(An aside: this isn't the only comic where I've seen you use the "water stream" graphic in a situation where one of the "height" props would probably be better.)
[Click to view comic: 'Tree-hugger Gone Wild']
This one has too obvious a premise and too weak a joke to be any good. Shock humor is rarely effective on StripCreator: we have almost no restrictions on the content of comics, so you're not breaking any taboos, and we've heard this kind of thing many times before.
A couple of other comics that are "too obvious to be funny" are the one about the nun having sex and the one about the Frenchman being cowardly.
Here are my three favorites:
[Click to view comic: 'Eye of the Beholder']
This is clever; I don't think anyone's noticed the similarity between those two characters before.
[Click to view comic: 'Un-True Calling']
I wasn't expecting the twist in the last panel. It was funny and quick.
[Click to view comic: 'Party DOWN !!!']
Here you're doing exactly what I wanted you to do with the earlier Tea Party comic: you show Tea Partiers acting crazy instead of telling us that they're crazy. Contrasting them with "normal" tea parties is an effective technique.
I think you have promise. Keep working at it.
The what mentioned above is total fiction. Please don't take it seriously!