Complete more shops successfully. Every time you do, you will get "points" which add to your reputation. When you get enough "points" your reputation will go up levels and allow you to self-assign more shops.
If you want to have more assigned, you can always email the schedulers and ask them. They can bypass your self-assign limit.
It really varies. Getting up the first level is quick. However, each level beyond that takes progressively longer. I do very little shopping through iSS, and have been on level 5 (?) for about a year. I don't know my self-assign limit and I generally don't want more than a few shops that are available to me.
Hi Kristi, if you click on your main badge level you can see what your percentage is right now and you can track how much it goes up each time one of your shops is approved. That's how I do it. Currently my level goes up one percent each time I complete a shop (once it's approved), and I'm at almost 80%. So I figure I have to complete another 20 shops to get to a badge count of 4. It's taken me a year lol to get this far because I haven't been doing as many on here as I'd like.