Brighter (not just lighter - you want intense color) paints tend to work best - this stuff is glowing, after all.
Here is James Wappel using Vallejo's fluorescent paints (among others) to great effect on a lava base (topped with a mostly naked model, if that's an issue from where you're viewing).
You'll notice that there isn't that much actual red visible in the finished shots. I think that's part of the success of his technique - red is integral to the process, but doesn't really appear in the final product, on its own. It tints the various colors around it, giving a sense of slightly cooler peripheries by both darkening and dulling the colors. Fluorescent yellows and oranges dominate the actual lava, which is what really conveys the sense of heat. I also love how he mottles and breaks up the lava, which many people don't do (smooth blends seem to be the order of the day for most "pro" lava I come across), but that's somewhat tangential.
I've seen lovely lava painted with the usual red>orange>yellow>white transitions, of course, but they never have quite the same punch, to my eye. In those cases, color distribution becomes even more crucial, as the paints are dull by nature - any sense of glowing brightness is
entirely illusory, requiring no small degree of skill to manufacture.
TLDR: If you want to improve your results without having to change your method, change your paints.