I tend to fish lures on reservoirs in these circumstances;
- Fishing to lethargic fish in cold water, frequently but not invariably deep and always slow
- Speculatively at any time when there are few clues about fish location and likely food
- for daphnia feeders, mostly from midsummer into the autumn
- For fry feeders, late summer through to season's end
So - for the first purpose, all or predominantly black lures are first choice, with a white lure and something like an oversize damsel or brown woolly b*gg*r in reserve; similarly for the second purpose where I may use a bright coloured one and / or speed up the retrieve as a shock tactic; match the colour of the daphnia for the third, the little creatures are either orange or green so those are the colours or a yellow lure is a good hedged bet, all these are fished quite fast; and white lures for fry, usually fished slow.
About the only other tactic worth mentioning is a muddler or booby, sprayed with floatant and fished on a floating line, fast through the ripple. Again a summer or early autumn tactic.
Hope this helps.