I don't know where you are at in terms of typing, but if you do know how to touch type and know where every keys are located, then I have tips for you.

Just 2 years ago, I was used to hunt-and-peck style of typing with speed around ~35-40 wpm.
Last year, I started learning touch typing with multiple websites including keybr.com, keyhero.com, typing.com, typeracer.com etc.. Once I have learned touch typing, I practiced almost everyday at least 2 hrs. It improved my speed to around ~70-80 wpm which took me around a month to reach that speed from 40 wpm.

Still, I wanted to improve my speed more despite it was fast enough. For 3 months I practiced typing for hours each day, and my typing speed was locked on ~80 wpm (well sometimes I reached 100 wpm couple times but mostly 80 wpm).

Well, at that point I decided to quit since it didn't made any progress. And when I came back after 6 months of "break," I just wanted to type for fun to see where I am at. Suddenly, my typing speed was at ~90-100 wpm.

My theory is that you will improve speed by taking breaks once in a while (like practice typing every day for a week, and rest 2 weeks... and so on).

Currently, my average typing speed is at above 100 wpm.
Hope this helps.