Also touching up on what Garry2rs said about figuring out the feeding patterns from area to area, one of the best modo's I've ever heard from a fisherman, specifically a Steelheader fishing buddy, since steelhead are quite picky sometimes about what comes there way. He mentioned it to me once, and it always stuck with me ever since, "Let the fish decide what they want to eat today, rather than trying to dicate what they should bite, by bringing a few hot lures." That particular time, I brought just pink worms & roe, thinking I was going to do well, but as it turned out, having a variety of lures that the fish hadn't see before seemed to be the trick of the day. And it was true, he just kept switchin up till the fish started biting whatever he was giving them. Sometimes you have to take the time to figure the fish out, and you should have a easier time out there. So always bring a variety of baits in different shapes, colors and sizes.
Here's another tip to add to what Garry2rs advised, is STRUCTURE , if you don't know what too look for, you may be missing out on fish bigtime, this especially holds true to big lakes you've never fished before. Always be on the look-out for weedbeds, weedbed edges, very rocky shoals, sandy to rock shoals, lily pads & sunker timber, docks, you name it, and also signs of life like swarms of minnows and frogs too. I went to a bass pond once, noticed a few frogs here & there, said to myself "I should try the skipper pop", what do ya know, I caught plenty of bass that day on that "Leopard frog" patterned topwater bait. TRY MATCHING THE HATCH, or even do the opposite and throw them something that they have NEVER seen before.
Lastly, 95% of the time, most importantly, PRESENTATION, I don't care if you have a $1000 lure on hand, if you don't know how to use it, its completely USELESS. You really have to think in terms of how the fish feed and what they might be after that day. During sunny conditions, and even worse, with sunny & clear water conditions, the fish will tend to be a lot more picky, thats where "presentation" really comes into play, if you can imitate what they're going after to the dot, you'll probably be putting on a clinic that trip !