Lots of good advice already! I'm in the middle of my second Kickstarter right now, so here's some of my tips:
-MAKE A VIDEO! Not having a video for your comic Kickstarter is a nail in the coffin. People are much more likely to engage with a video than read a wall of text, and Kickstarter staff themselves urge creators to include one. I strongly recommend showing off artwork from the comic during your video-- don't just point a webcam at yourself and talk about it. We want to see what the comic looks like!
-You're selling a product. Do show people the creator behind the book and why you think this project's important, but don't treat it as a charity. People don't pledge to Kickstarters because they want to fulfill someone's dreams-- they want cool stuff.
Case in point, I saw one comic KS where the video was just the creator talking at length about how they always wanted to make comics since they were little, and not once did they actually talk about THE COMIC. Unsurprisingly, that one didn't fund. :v
-Media mail! This is a US thing, I don't know how it is in other countries-- but if you're sending books domestically, you can send them via media mail. This is way cheaper than first class, and a few bucks saved off every package will save you a ton on shipping.
-Reach out to press at least 2 weeks in advance. Make a list of any review sites, blogs, podcasts, etc that feature comics, especially indie stuff. Write personalized review requests and ask if they'd be willing to do a shoutout for your campaign. I also recommend creating a press release package-- this is an article you write yourself about the comic and the campaign, which writers can easily take and throw up on their website. Be sure to include some hi-res images with your press release.
-Thank every backer! Whenever I get a new pledge, I reach out to them with a personal message to thank them and let them know that I'm available if they have questions. People really appreciate it when they know you acknowledge their support, and don't just view them as a number.
-Plan stretch goals carefully. Make sure any stretch goals aren't going to bloat your shipping costs! For this reason, I made my stretch goals things that improve the book itself-- an additional art section, a mini comic, a fancier cover. I had thought of offering a poster, until I realized that would have to ship as a separate package. So plan carefully.
Also, consider when you want to announce stretch goals. Some like to have them all up front from the beginning, some announce them mid-way through, others trickle them slowly over the course of the campaign. I chose to announce mine at the 50% funding mark to maintain momentum and get some more excitement going during the mid-campaign slump. Speaking of...
THE PLATEAU. This happens to just about every single project. If you've done your homework and prepared accordingly, chances are you'll get a bunch of pledges when you launch, and for the next day or two. But then, things slow down dramatically. You might only get 2 new backers a day.
This is the MOST important time to stay on top of promoting your campaign daily, reaching out to new media outlets, introducing new rewards/stretch goals, or doing something fun like a livestream. Share something interesting about the campaign 2-3 times a day (space it out, preferably). Since there's no sense of urgency, you've got to get people excited yourself. Show them why you love your comic and why they should love it too. Once you near the final 72 hours of your campaign, you can expect momentum to pick back up.
Also ditto what @nikaalexandra says about researching other campaigns. I recommend looking at not just the successful campaigns, but the flops too. Look for the campaigns ending soon that didn't fund, and examine their pages-- what about their project do you find unappealing/confusing?
I hope that helps! I think the biggest takeaway is-- Kickstarters are WORK!! Once you hit the launch button, you're only just starting. Remember to take care of yourself during this time!
