When applying mortar for the horizontal joints in brickwork. First form it into a workable shape on the trowel so that it can be rolled off in one smooth movement. Level the mortar out to a thickness of about 12 mm 1 in.
Lay the next course of bricks by applying the mortar for the vertical joints to the end of the brick before it is laid. If the mortar is applied after the brick is laid if can push it out of line.
First ‘butter’ one end of a brick with mortar and then spread it out to the same thickness as the horizontal joints. Slice off any excess mortar and tap the brick up against the brick already in position to compress the mortar thickness to 10mm 2in.