CustomMade is an interesting venue. I've been a maker on there for probably a year and a half now and noticed a few things.
It's to your benefit to bid on job and watch the job board. Don't wait for buyers to find you, especially if they post a specific need that you can fill. Also watch for buyers to grab your images and post a bid request from other makers. Many buyers don't know the way the site works.
Also as of about 5 months ago, if you accept credit cards, you have to accept through their processor. It works well, but between CustomMade's cut and the credit card processors cut, price your proposals accordingly or you'll loose around 13% off the top.
Otherwise, I've had some great leads and great sales through them. They're really helpful to their makers and jumped through hoops to address anything I've asked from them.
Congrats and best of luck!