There are many factors that affects your sales. Below is a list that you may want to consider with some explanations of what you can do about it.
- Approved on weekend - If your works happened to be approved on weekend, then you will definitely misses a good chance for good downloads. Without good downloads, your new vectors will be "buried" by other new vectors that approved on weekdays. Although it is good to be approved on Monday, but I realize that you have no control over this, especially agency like Shutterstock could approved your vector between few hours or 2 weeks later. However, some agencies like DepositPhotos does have some consistency in approving your stuff. So, plan it right ;)
- Summer holiday - Summer holiday are often referred to months from June to August. Contributors consider these as slow months. While, it is good to take a break in these 3 months because there are less downloads - it also means that your competitors are taking a break too. So, visibility of your vectors got higher too.
- Good downloads months - March, April, May, October and November are good months. You should not miss these five months. Work hard before and during them.
- Trends - Should I follow trends? Now, everybody is talking about flat icons. And Christmas is coming too. The answer is yes, you should follow trends and never go against it.
- Should I draw more vectors first, and upload all at once? No, you should upload as often as possible. It is tiring and daunting to think of good keywords. Uploading 30 vectors at once could take you 2-3 days. Also, uploading a lot of vectors at one time could potentially increase your rejection rate.
As a conclusion, I do believe timing is something not to be ignored if you want to maximize your profit. Good luck.