Half the point of publishing/printing your work is to gain new followers, so no, I didn't wait! For me, it was "proof of concept". I used the print run to gauge interest and test if it could make money.
Online sales are real slow (or non-existent) until you get a large fan base, so with printed work you need to sell it to people directly. Being able to pick up an item and look at it has a HUGE impact on if someone will buy an unknown property.
I took my first run to sell at a convention and I advertised around town and within the con by putting up flyers at local colleges, comic stores, art stores, cafes, and within the venue during the event (though this one often isn't allowed, you'd have to ask). I'll expand more on cons in your 3rd question.
Yep! I would google the differences between consignment and selling wholesale, as both are common when selling with retailers. I was lucky and most people around here were fine with wholesale (which is generally preferred since it's guaranteed money). They tend to prefer volumes with a barcode and ISBN already present, but comic shops are more lax on that and sometimes prefer issues. You will need both (barcode/ISBN) if you plan to sell at a book store, though.
Your success at a convention is not based on being a known artist--it's where people go to discover new media, find art of fandoms they like, or they just browse around to see what looks cool. The impulse buy is your friend, and there are a lot of people who specifically seek out original works. If anything, they are specifically TO build an audience. My audience has some overlap between online and conventions, but by and large they are two completely separate groups.
How lucrative it is for you is based on a lot of factors, but here are some common ones:
- Quality of your content
- Eye catching display to draw them over (At least get some table easels to prop things up vertically and have a banner)
- Good customer service
- Audience & size of the specific event (going too small means you may not get any traffic, while going too big may mean you get drowned out by the competition. Starting out, I stuck to cons between 2-7k because I got noticed. Comic cons also have wildly different audiences than anime cons, for example, and your mileage may vary on who responds to your work.)
- Market-appropriate pricing (Prices should be at least 4x production cost, but also research some common pricing at cons. Sometimes you have to take a hit or find another company to print your stuff for cheaper, but never price less than 2x your costs)
In general, you also want to sell at least three different types of merchandise at different price points (low, med, and high) to cater to customers of all wallet sizes, and having a large variety of designs or books will allow you to hit a larger percentage of the audience. But, starting out, it's okay to not have a big variety--inventory is usually something you build over time.
Also, don't get more than 5-10 of each item you're selling, maybe 25 of your comic. You often won't sell more than that of each thing at a con and you shouldn't be ordering in bulk until you've tested its selling potential. I made a huge mistake of printing 50 of each poster I made for my first con and I had them for YEARS before deciding to pitch them--don't be me. XD
At first, stay local, just try to break even, and go from there. Conventions are an investment and you'll learn a lot just by doing them. I would suggest joining and searching through the facebook group Artist Alley Network International for a lot of great information.