Thinking about tones when you speak.....

[Demonic_Duck]

Agree this is valuable, but it is extremely hard to find. Politeness and fatigue get in the way. After correcting you 12 times in the first 20 minutes, most people just give up on the project no matter how strongly you have urged them to be strict with you regarding pronunciation.

This is so true.  I have several Chinese friends to practice with and no matter how often I tell them to correct my pronunciation, they soon slack off saying they know what I mean.

Once you get to a point when you're reasonably confident on most of your tones/pronunciation, you can simply pick up on those words that you're not sure about and ask for confirmation. Sometimes I just repeat the word in different plausible-seeming combinations of tones - with some friends this works and they repeat the correct one, whilst others just say "嗯" (having understood) and I have to ask directly. Any rate, it does the job, at the possible risk of annoying my friends. I think most of them just find it endearing though - I have a colleague who's equally conscientious about her English pronunciation, despite being a long way from basic fluency, and I respect her for it.