Give your artwork as much thought as your title.
Due to the way podcasts are searched and discovered, the artwork for your show is often more impactful than the title of the podcast itself.
A pro makes a big difference.
Unless you have a graphic design background it's likely that an expert graphic designer can add huge value here at a very affordable price.
Episode specific artwork should be a stretch goal.
To start with, focus on generic episode artwork and don't worry about having new artwork for each episode until you have the resources to dedicate to it.
How Can I Improve?
Assess where your artwork is at currently. Does it catch your eye? Does it match your current branding? Is it an elegant design reflective of who you are?
Consult an expert. I have teamed up with graphic designer, Dan, who offers a package specifically for Be Heard podcasters. See here for more info.
When looking for new ideas or choosing between designs, do a bit of market research and ask some people for feedback. Try to ask your target audience where possible.
Simpler the better - don't try and cram lots of information in an image;
Expert graphic designers add a lot of value;
Podcast artwork is one of the most important factors in getting clicks from new listeners.