It only took me one time to try burning and really like it. However it took me a few years to where I did decent work and learned decent shading

The first time I tried leather it didn't go very well, but after a few attempts I got to where I liked it.
Susan's patterns are really good to use for burning I have seen some great results from them.
There are several free programs to reduce the size of your image files, if you don't have one. Using a PC?