While just pouring some play sand in to a can of porch and deck paint seems like a great idea to help an area become more slip-free, there are some better and more durable alternatives on the market, including commercial additives that can be used and give great results.
What not to use
Play sand in the paint can? After all, many people sprinkle sand on their steps and paths to add traction during winter for snow and ice. This would seem to be just going one step further. However, adding regular coarse or play sand to paint does not usually work out too well. It is extremely difficult to keep mixed up well while you are painting. Also, the finished product can be a little rough on feet and other body parts that it comes in contact with. Finally, using coarse sand seems to make the paint flake and peel much sooner than is normal.
Boat owners use non-slip paints and paint additives on the surfaces of their vessels to keep them up-top and out of the ocean. The old school method of coating boats in non-skid paint was adding finely ground walnut shells to the paint and using that. Newer methods involve stirring in an additive available at marine supply shops. It works well mixed into the paint, provided it's kept stirred frequently during application to keep the additive suspended. It's made of very fine glass and feels like very fine sand to the touch. If applied correctly, the surface will look very smooth but also have a good grip.
If you wander the aisles of your local B&Q or Homebase, you should come across Behr's Non Skid Floor Finish Additive. This is the landlubber's equivalent to the marine additives mentioned above and will do the same sort of job for your front steps. It does not change the colour of the paint, and each package mixes with 4.5 litres (1 gallon) of paint to coat decks, steps, walkways and even pool decks for extra traction. The manufacturer recommends using it with concrete floor paint for best results.