Do as many exercises as you can from sites like rubyquiz.com. Use any language you like and just skip problems that are Ruby specific. Don’t stop just because you reach a working solution. Spend lots of time editing and reorganizing your code to make it clean and clear. With practice that will come to you more naturally but you have to put in effort to develop the habits.

Also, get other people to review your code. There are subreddits for that on the old site. Here I guess just use !programming.