(I think some of my comments got cut off, you might have to hover your mouse on each one and scroll down to read the entire comment.)

I dunno if you're gonna read this but you're on the right track! Learning how to type without looking at the keyboard is one of the biggest steps to success, and you made it already, so give yourself a big pat on the back!

To type even faster, there are three main tips:
1) Slow down and focus on accuracy. Even though that sounds counterintuitive, having high accuracy really works wonders in the long run. Whenever you type, especially at higher speeds, you get into a 'flow state' where your fingers just glide effortlessly through the words without you really thinking about it. However, if you have a lot of errors, you will have to break your flow state and go back and correct your mistakes, which will drop your wpm significantly. Focus on accuracy, and speed will come along with it.

2) Start trying to group letters and short words together. At 50 wpm, you probably type each letter one by one, for example, you would type "keyboard" k-e-y-b-o-a-r-d. However, if you start typing words in chunks, you'll spend less time thinking about each letter and more time actually typing. The word "keyboard" can be split into key-bo-ard. Eventually, you wanna be able to type the entire word in one go. "keyboard". I'd say a good place to start would be practicing really common words, like "and", "with", "that", as well as common letter combinations like "ing", "tion", and "ther".

3) As you're typing a word, start reading ahead at the next word. This will give you some time to prepare and ready your fingers once you hit that space bar. For example, if I'm typing the quote "The quick brown fox jumps over the lazy dog", as I'm typing "jumps", I'm already looking at the word "over", and I'm readying my right ring finger to type the letter 'o' as soon as I hit space.

But most importantly, practice! If you can, try to dedicate 15 - 30 minutes each day to practice your typing skills. However, don't overwork your fingers, and take frequent breaks! I'd recommend taking a 1 minute break for every 3 - 5 minutes of continuous typing, which (hopefully) will help reduce your chances of getting arthritis.

I wish you luck on your typing journey, and I hope you can break 100 wpm soon!