On dull days, we're gifted with deep colours. The temptation is often to cash in on this, by raising the overall apparent illumination (and by extension, saturation) by raising the midtones. If you want to remain true to the fact it was a dull day, try not raising the midtones.
Then when you raise up some of the highlights, as I did with the lamp bulbs in this photo, you get a remarkable contrast between those high key areas and the overall drab scene. Use Curves, and make sure you keep an interesting range of tones within each of the two contrasting areas, by carefully placing two moderately steep slopes in that curve.