I would say keep at it. I don't want to say its a numbers game but you have to keep creating and promoting. Do you promote your products on social media channels? It isn't enough to let the platforms advertise for you. Share your products on your favorite sites including your website if you have one.
You don't say how many products you have but there are some Zazzle stores that have nearly 50,000 products.
Regarding asking friends and family, yes, by all means, do that. However, I have found two scenarios that occur, one they say they like it but they'll never buy it. They may not want to hurt your feelings by being honest with you. The other thing that may occur, is they will be too critical and make you doubt your creativity.
I would suggest you look at the best sellers on Zazzle and be honest with yourself about how yours compares.
Keep creating, promoting and improving your products.