If you intend to turn this into a complete deck, at some point you will have to learn some of the software like Photoshop. There's really no way around that, it's just a fact of the design process these days. I'll say that designing a complete deck is HARD. Even being fully versed in the software, it's a lot of work and takes some real dedication.
I think that if you have the interest, you would be well-served in getting yourself a trial version of photoshop, or perhaps a free image editor like GIMP and spending some time learning the basics. Experiment and try things and over time you'll learn what works and what doesn't for you personally.
Having the eye of a designer takes time, so study decks that you like, look at details, and explore things beyond just cards. Get yourself some design books or magazines and eventually you will train your brain to start to recognize positive aspects of design and it won't be as mysterious.
Keep at it!