WPM speed is highly dependent on the content that you're typing.
For sensible text, such as day to day newspaper, one can achieve upwards of 160wpm, sean wrona, the only dude who does this on text that's UNPRACTICED.
Lets say you have a text full of words you have never read before. Then speed will drop dramatically no matter how fast "you think you are"
You see alotta flakes going around telling people they can type 140+ 160+.. what they mean is they can do that on something like type racer, where there is only a total of 30 different lines of text, of which they typed a million times for the past 3 years.
Pretty stupid and useless...
For general improvement to your typing speed, Don't use the wpm measurement as the goal, because it is not indicative of your capacity in "different situations"
I recommend 10 fastfingers for practicing the spacebar followup chain, because it follows almost every word.
And for trasncription speed, if you're REALLY into it, try out
http://patorjk.com/typing-speed-test/in the settings, change it to SAT words. this way you won't be constantly typing words you know, thus your practice will be more varied.