Stuck for keywords? Start with what you'd tell someone holding your product.
Make three small groups
For a blue ceramic mug, you might write:
What it is: ceramic mug, pottery mug.
What it looks like: blue ceramic mug, blue glaze mug.
How it's used: coffee mug.
Add options only when you offer them. “Personalized mug” needs a personalization option.
Pick a few to explore
Choose one phrase and search it in Marmalead. Do the products look like the kind of item you make?
Keep useful phrases in a Keyword List named for your product. Shared words are fine, and the groups don't need equal numbers of tags.
A handful of phrases you can use is enough to start.