wave reflow
Hi kobik:
In wave soldering, the SMT components are patches berfore solded with a special glue. Then PCB cross trought a wave hot of tin, then the tin is paste on the empty metal of components and PCB. This method can used only in one side of PCB, and is not temperature controled method, so is more imprecise than reflow.
The components must be place in same directions attempts to not make "shadows" of tin when you are soldering.
In reflow, first it's make a plate (stencil) with holes in the position of pads to be solder, the you put the stencil over the PCB, and put hot tin over the stencil, then the tin will solde over the pads, after it, you remove the stencil and the PCB has tin on the pads. Now you paste the components on the PCB with a glue, and then put the PCB with components inside a temperature controled furnace, so the tin will solder to components.
There's not special attention in placements for reflow method.