Wiring switch outlet to be half hot
If you have conduit you will have to pull a black #12 or #14 copper wire from the light switch to the outlet. Pigtail this wire in the switch box to the black (feed) wire going to the switch. at the outlet connect the black wire to the screw next to the red wire. Now remove, break off, the tab by the brass screws.
If you have Romex wiring, you will need to replace the /2 cable with 12/3 or 14/3 cable, black, red, white with bare ground. Wire the switch and outlet with the new wire in the same positions as above.