... w.r.t. dirty, tea coloured water and trolling... I found this...


If the water you are fishing is rather “tea-stained†or a bit dirty or “cloudyâ€, then the gold color lure would be your best choice. Gold has fantastic reflective qualities in tea-stained/dirty water – much better that silver.
If you are fishing down 20 feet deep & catching plenty of fish on a particular lure, and then the fishing slows & you find out the fish have moved deeper – the same lure may not be as effective.
This is because as you go deeper, the reflective quality changes & thus the appearance changes. So the next time you ask “what color did you catch them on†the next question should be “how deep were you fishing�
http://www.thundermistfishingtips.com/4-tips-on-choosing-the-perfect-fishing-lure-color
Take your favorite jig and tie on a small piece of crystal flash or tinsel. I like to tie on several colors, gold, blue, silver or what ever you think will work. This adds extra flash to the bait and this little added flash can make the difference in a fish seeing your bait or passing it by.
If you fish soft plastic baits, you can let them soak in pogy oil for several weeks, before attaching them to the hook. This will add a scent to them that will last a long time and for some reason the pogy oil makes these rubber baits very tough and difficult for the fish to get off of the hook. The down side to this is it is messy.
http://www.landbigfish.com/articles/default.cfm?ID=1613
Algae, silt and pollution present in the water will cause light to scatter changing the depth wavelengths will travel. In the ocean water tends to be clearer, where as inland lakes and streams tend to be filled with eroded materials, pollution and garbage.
When fishing topwater lures, color is far less important than size, shape and action. A fish coming up below a surface or shallow running lure has the light behind it, making the lure appear grey or black. Try it for yourself - hold a fluorescent lure up to the sun and view it from below. Black and dark colors remain the best for surface lures because they throw a great silhouette.
http://www.colourlovers.com/blog/2008/07/09/fish-on-selecting-the-best-lure-colors