Manual transformer winding - dots convention
Winding from top to bottom or bottom to top does not change the "dot" (which represents the direction of the magnetic north/south pole for a given current direction). 

You can use the "right hand rule" to keep this straight. 



Place your right hand around the coil with your fingers in the direction of current flow. Your thumb points to the North magnetic pole. The ends with the "dot" will be the ones that create the same direction of magnetic field when current flows from that end to the other.