Using the Redbubble tag generator tool https://bit.ly/3vaIMoC can be a good way to get started with finding tags for your products. The tool can suggest relevant tags based on your product title and description, as well as your artwork. It's important to use tags that accurately describe your product and are relevant to your target audience.
In addition to using the tag generator tool, there are a few other strategies you can try to increase sales on Redbubble: