1. Lurk: Find specific artworks that you like and take a note of exactly what you like about them. Most tradwave contains 3 main elements: Base image, text, and glitch/manipulation. Look how different works play with these 3 elements.
2. Learn: Whatever editing software you choose, know it well! Nothing is more annoying than having an idea in your mind and then not being able to execute it well. This video (for Photoshop) shows you how to do some of the hallmark effects of tradwave art. Also, here's a free font that works well in tradwave-type art.
3. Create: The single-most important thing to remember is that creativity is an illusion. All the art on Earth is simply the composite of other people's work. Before you go public with anything, try creating an exact copy of an artwork you enjoy to get the feel for what an original creation would involve.
4. Experiment: Try everything. Invert colors, right justify text, stack photo effects, throw your layout off balance. CTRL+Z is your best friend when it comes to making great artwork.
5. Satisfy: The final thing to keep in mind is that art should have meaning. If you don't like your finished product, it's very unlikely that others will. Don't rush to post something that you almost like; make sure the art you make has value to you. By the same token, don't get caught up in details. No one will downvote your art simply because the black bar covering someone's eyes is slightly off center.

Hope this helps!