Check out this great tutorial from Propellerheads Mattias on how to mix vocals. In this Reason Tips video Mattias gives you some valuable pointers on mixing

Since vocals are often what carries the track, it’s important to get them sitting

More Reason Mixing Tips – Useful Information

Don’t forget to check out Gary Bromham’s guide to vocal recording: http://goo.gl/Vjyek. Getting the right source audio is crucial to improving your mixes, this tutorial outlines the basics for capturing great vocals.