Question about ear training for improved soloing

I'm currently trying to incorporate more ear training into my routine in order to improve my solos. I've heard that playing vocal melodies to songs is good practice. When doing so though, do you have to check that you actually got it correct? And how would you even do so? Or...would you simply progress and improve over time, even without checking yourself?

I'd also like to do a more formal ear training / transcribing course - is anyone aware of good online courses for guitar? Any other advice?