Avoid plastering in patches or only in joints on a textured wallpaper
If you plaster in spots or only in the joints of e.g. textured wallpaper you get small smooth areas mixed with patterned areas. Plastering the whole wall instead, or tear off all the wallpaper before plastering.
Use an adequate amount of plaster in one round
When too much plaster is used at once, the wall may be raised and the sanding process becomes more tedious.
Pre-glue or prime after plastering
If you don’t pre-glue or paint on the plaster, you risk it absorbing the wallpaper adhesive and the wallpaper will not stick well. It may therefore be important to paint over the plastered area before wallpapering.