Cement, in fact is not that difficult to paint. This is due to one simple effect, hardened cement is basically porous to some extent, even on the surface. Hardened cement can be pained with the help of three principle techniques.
These are namely, oil painting or acrylic painting, painting with a primer and finally painting with a separate specialized cement paint. Now there is nothing special about a cement paint except the fact that it is a paint that water proofs a cemented layer.
Now first off, prepare a base for the paint. Here as application surface is concrete, so it would not be very difficult. Your first step should be cleaning the surface with a proper TSP (Trisodium phosphate) based solution. Make sure that the cement is not cracked or fragmented or is showing any sign of being brittle or soft at any specified point.
If such a deformity exists in the cement, then make sure that you get a cement sealer and apply the same over the deformity. In case, if the patch of cement that you want to paint is too porous or too uneven and rough, then you will have to give in a coat or two of the primer before you apply the paint.
One of the most crucial cement painting techniques is determining the texture of how you want it to be. The property of a paint coat over cement is that your brush pattern textures the entire surface which you have painted, and it becomes significantly visible. Hence the pattern or your brush strokes need to come out uniform and in the right orientation.
For example, upward to downward strokes come out to be really well when done on a wall. For the corners you can take up horizontal strokes. Overall, decide how your pattern is going to be and how may coats you are going to take up.
In fact, you can also follow the same pattern for the primer, it basically enhances uniformity. Most concrete floor painting techniques lay a heavy emphasis on strokes and stroking techniques.
For example, let's say you want to paint your porch or walk around of the house to resemble small slabs or tiles of stones. In such a case give a darker or a more hospitable color of say gray or brown on the cement surface. Then give another coat where you can trace out, very bluntly the entire frame-work of tile, with a pencil or chalk.
Next take up the main color scheme of say black or dark brown, and paint over on two or three coats over the base paint. In some cases you can leave out the borderline gap seen between two tiles, giving it a very realistic effect. You can follow the same technique for painting concrete floors. You can try designs like a brick wall, stone, bare ground etc.
After you are done with the painting you can apply a thick after coat to waterproof the paint and thereby, preserve the surface.