Hi, BoB. There is not need to texture your drywall. In fact, that will make it much more difficult and less attractive for faux painting.
Do sand the areas that have been taped and filled with a sanding block and sanding screen, both of which are readily available at home centers. Then apply a coat of primer/sealer. B-I-N and Kilz are both good brands. You can roll this on. Now you are ready to paint this any way you choose.