There's no formula to it, so I can't give you very specific help, but here are some things to keep in mind:
The opening pages are your opportunity to grab a reader's attention. Fail that, and they won't keep reading.
- The pages should be interesting/exciting, not filler.
- The early pages should represent your comic's feel/tone/atmosphere. If they don't, you risk not reaching your target audience, and later losing the (non-target) audience you gain via faulty expectations.
- Introduce, or at least hint at the story's conflict (if it's straight-forward), or its themes.
Remember that new readers don't know the story as well as you do. A lot of them probably wouldn't even have read the description/"about" blurb. Don't expect them to know anything specific to your story yet, and don't expect them to care about anything.
- Do not go into details. Readers forget details they don't yet care about. Introduce them later, when the readers become interested in your story.
- Do not introduce too many characters. Same as above, but also people tend to have a hard time remembering things if they learn too much new stuff at once.
Show the readers what you can do! Make them fall in love with your story/characters.
- Does the comic take place in an interesting location? Show it off (and your drawing skills) with an establishing shot.
- DO NOT use an infodump (a bunch of text that explains the world/backstory/plot). It's information readers don't care about yet, and it looks lazy. This goes for your whole story, really: Show, don't tell.
- Introduce at least one of the principal characters, preferably the one that's most distinct/memorable. Someone we want to learn more about. If the reader doesn't want to learn more about your world/characters after a few pages, why should they keep reading?
Really, it comes down to this: Introduce questions, and make readers want to know the answers! But obviously, don't literally ask questions. Make the reader subconsciously ask them xP
How you do this depends entirely on your storytelling style and your specific story.