As Eustacia says, there are many tutors on italki who can help with conversation. Depending on your level of English, this may well prove effective. Personally, I would recommend using other methods like reading to improve vocabulary, because your vocabulary will only ever be only as good as the person you're talking to, and it's maybe not the most efficient way to obtain it, especially if you don't want to revise. Anyway, using the search facility, you can choose your tutor based on different interests and characteristics that are important to you. Good luck!