Protect any door frames, sockets, skirting, light switches, etc. with making tape. Apply the tape in short sections and press down firmly. Use your nails or a filling knife to ensure proper bonding between the tape and the surface, to avoid any paint seeping in.
Tip: If you are painting fresh, unpainted walls or walls that have been filled and sanded in places, it is recommended that you apply a coat of suitable primer and allow it to dry before you begin painting.