I've always had problems with painting realistic bases. Some have worked others I've been ultimately disappointed by and there's nothing worse than having a cool looking model spoiled by a shoddy base. When I was painting my Empire WFB army in uni I only put model railway gravel down. I remember distinctly congratulating myself for this decision because they looked neat and didn't require any extra painting, figures painted, gravel on, job done [I must photograph those figures...].
Of course doing a red planet means that I could have got red oxide model railway gravel to do the same. They also come in a variety of grades, small, medium and large. Having a mix is really useful as discussed when I bought myself that bag of sharp sand. In the end cost won and having painted the, slightly thinned] £1 Vermillion acrylic art paint on the sand I fretted about how I was going to make it work. Lets bring my old 'friends' - my Son's Rippers to illustrate my concerns
As you can see the Vermillion matched perfectly our Red Planet terrain base map. The slightly thinned paint allowing the natural tones of the sand and lava stones to show through. I'd also fretted about the base edges as the pigment in the Vermillion was quite thin, successive coats, even on a white undercoat didn't work. I asked the manager in my local GW store if I could try some Mechrite Red on the edge and I was blown away. If I'd have left the Vermillion it would have been patchy in places and would have blended near invisibly with the board but the darker Mechrite makes them stand out so much and yet still works because it's tonally similar to the boards shadows, as you can see. At any rate most GW basses are green with a brown border so having the sides a different colour clearly works or they wouldn't have been doing it this way since I was a lad. The finish was certainly an improvement, so I bought a pot there and then [good sales technique on behalf of the manager there].
So all my bases were now Vermillion and Mechrite red but that little voice was telling me leaving it plain was not good. I needed to add shading and highlights regardless of how long this may take. The other voice was telling me to leave well enough alone before I messed them all up. I cut some strips of hardboard and added sand and tried four or five different versions to get to my happy place. Bearing in mind I was dealing with the same issues with hills and craters for the rest of the scenery, this was a major deal breaker. Eventually I ended up with a recipe I was happy with. More importantly I reasoned that although the Vermillion matched my print out I may not always be using that for our battlefield. If I have to paint one then surely that will match the base so it's better to match something I can control in the future instead of something I may discard.
My recipe ended up so simple I'm quite surprised it took me so long to get it right. After the Vermillion I used a Badab Black wash, I'd tried, Devlan Mud and also thinned Chaos Black, and thinned Chestnut Brown craft paint [cheaper than the washes] and decided Badab Black worked best and as I hadn't used it much in the rest of the army I had more than the Devlan Mud left so it was not the cheapest option but the second best. A quick dry brush with the Vermilion brought back some of the colour, then adding some bronzed flesh and a very light drybrush on some of the bigger stones and edges lifted the texture just that little bit.
Finally, the masterstroke was some Bonewhite stones. Picking out the odd one scattered here and there really made the base 'pop'. In some ways I now find the bases even more interesting to look at than the model! That may be completely wrong but I love looking at all the texture. It's not extremely difficult to do either, the graded sharp sand pretty much presents which little stone to make Bonewhite and all you need is a bit of patience and a steady hand and job done. Admittedly I then had to go back and touch up all the little mistakes my drybrushing made but overall, after many hours I was ecstatic with the results and satisfied I'd ignored the lazy little voice.
So lets bring back my old friend - Broodlord in a Body Warmer so you can see the difference, not to mention the highlighted talons versus plain black ones. I think it was the right decision in both instances. Hope you give Red Planet basing a go.