Or Illustrator. There are many other less professional image editing softwares...but they have setbacks.

I started as a computer programmer who never knew a thing about design. Then I became close friends with a graphic designer who was intrigued by programming. Eventually, we evened out each others skills.

Make friends with designers. Study design. Always remember that simple and clean can never be wrong. Study professional templates and sites. There are millions out there. If you like, I can post some links of portfolio show off sites to research.