Fish finder is a must have item. Especially for what you're wanting to do. Otherwise, its like taking Stevie Wonder to a lake and saying, "See that lay down over there, pitch it between those two limbs that hang just 12" above the water". Seriously. That's a good anaology. :-) Taking a blind man fishing and asking that is completely hopeless.
They make very affordable fish finders now that have structure scan and sonar as well as GPS for around $300 price range. That is an invaluable resource for a kayak on a body of water. You can mark brushpiles, locate fish, etc.
As for time of year and tips, I defer to others. They should be moving up near channel swings and places of transition. That's very broad but basically you need to look for spots where fish can move vertically quickly without going far. I can't say it clearer than that but even then, that's not nearly enough explanation. I'm a graphic guy. I need pictures. Lol