It is possible to do some speaking practice alone, especially accent training. Choose a speaker of English who you like, someone who you think has a good accent. Try and find some videos of this person speaking on youtube or on DVD, and take a section that’s about 30 seconds long. Listen carefully to it: pay attention to the speed, the rhythm, the intonation and the pauses. Now go to Vocaroo (or use recording software on your PC) and record yourself saying the same lines. Now listen to yourself! Compare it with the original and record yourself again.  When you think you have a good recording, save it and play it at the same time as the original.