Learn to make 3d models right within unity using Umodeler! In this video we learn how to make a bottle with several variations within 10 minutes. Don't forget to watch the part about creating loop slices, doing box selects on hidden verts/edges, as well as how to use smoothing groups.
This method can be used to make bottles, vases, pots, baseball bats, chess pieces and more.
Buy uModeler here: https://www.assetstore.unity3d.com/en/?stay#!/content/80868