ok, so i wanted to make a bottle (coke bottle) and here is what happens:
and i wanted to make it like this:
please help
and i wanted to make it like this:
please help
The easier way to unwrap this part is with Cylinder Projection. Go into orthographic front or side view, unwrap and boom! You have a nice grid alike UV map. 
It is important to view your object aligned with a axis and in orthographic mode or else the projection is all screwy. You don’t need any seam. Blender will choose one for you. It may also rip some faces on the left to put them on the right or vice-versa but it works as well.
For the other faces (which you haven’t created yet), just reset their UV and shrink them all in a fully transparent corner of your texture. That will do the trick.