So they all need some work...pointers on ways to improve?
Like I said, your comics are like a Step One in a process that requires at least 5 steps. My advice would be to take the basic idea for your strip and jot it down in, say a Notepad document or something. Then, give it a day or so to bounce around in your head, see if you can find a way to make it wackier.
EXAMPLE 1: Jack In The Box(ers)
For this one, you've taken a pretty common joke and just kind of left it there. This dialogue might be snappier in real life, but it doesn't support the whole comic, mostly because the punchline becomes obvious in Panel Two. So, while workshopping this one, you may decide that slipping a "surprise" punchline into Panel Three will help this problem. I've made a comic to demonstrate how I'd handle it:
[Click to view comic: 'Vodekution (Part One)']
EXAMPLE 2: Voices
This comic has virtually no punchline in its present state. Again, workshopping this one and tossing it around before completing the comic could have benefitted you. I've also created a modest example of how this one could have been improved:
[Click to view comic: 'Vodekution (Part Two)']
Hope this helps. If you'd like someone to bounce ideas off of, feel free to IM me any time.
"He was cursed with a horrorshow of a face, like Guiseppe Archbold doing a study of mollusk tumors."