If you can find maps of where you're fishing that would definitely help... Google Earth could be your new best friend. It will allow you to go back in history and look at pictures of where you're fishing from years past.. it could have pictures of when the lake was low, which will show you creek channels, submerged rocks, trees, brush piles, etc.
Without electronics, it's kind of hard, but you can sometimes you can find humps just by seeing how the wind blows current. If you see wind blowing current out in open water, then find a spot that seems to be still, there is something going on there. It could be a hump, brush, or something else causing water to move around it and breakup the current. Doesn't make since, but it does.
Winter time is also a good time to go and scout shallow water.. many time it will be low and you'll find logs, stumps, rocks - all of these places will hold fish... especially if the grass has died down so that you can see into it. That's where I get my success for finding fish.
Going to new lakes that I don't have maps for, I'll hit the points with a texas rigged worm, and just feel out the bottom. You can find rocks, logs, stumps and all that jazz just by fishing SLOW with heavier weights than you would normally use. Heavy Jigs (1/2-1oz) are great for this too, and they'll catch fish in the winter time while you're searching.
Another good place to hit is a point where wind clashes from 2 different sides. Picture that you're facing a point. You have wind coming from the left and from the right. You look to your right and notice the wind is heavier on that side. Normally what I will do is move to the left side of the point, and cast straight out into the heavy wind.. let the bait sink right where it hits the water (leave your bail open, or feed line off your baitcaster). Fish normally (in my experience) face into the wind because they are lazy and don't want to work hard to get food. The lure coming in from the wind is "natural" to them and they are more likely to hit something coming at them as opposed to something sneaking up on them from behind.
Very seldom will I fish perpendicular to the bank... I like fishing at 45* angles. I'm trying to find out where exactly the bait is getting picked up. If I'm casting at an angle to the bank, and they keep picking it up 10' off the bank, then I'll move the boat 10' off the bank and begin casting parallel 10' out. Now I know where their strike zone is and you can rack up a good sack from doing that. If they quit hitting, I'll stay where I'm at and cast 45* back to the bank AND out to open water. They aren't going to move far and you can usually find them again.
Fishing under overhanging trees is a good tactic as well... you might just want to change up lures. My #1 lure for that is a texas rigged lizard. If possible, I'll pitch it in and create the loudest splash I can (I use 1/4oz tungsten bullet weights) trying to mimic a lizard falling out of the tree.
Another bit of advice is stick to the basic colors... Black, Green Pumpkin, Watermelon Seed, and White. I use these colors in clear to slightly stained water. For dark or murky waters, I don't use anything but Black, June Bug and Red Shad. June Bug and Red Shad are universal for clear or dark waters and you can't go wrong. 85% of the time in clear water I'm throwing Green Pumpkin. If I make any changes, the only thing I'll do is spray the tails with chartreuse garlic spray or dip. Or, I'll put some other bait attractant on them. I don't fish without something. MegaStrike is another thing I'll put on my lures - it works for me. In dark water, I don't do much of anything to the baits except to spray Yum Ribbontail 7.5 worms in JuneBug color with some Yum Shad attractant (cheap stuff at Wal-Mart)... again, this works for me.
Sorry this is long, but I'm trying to give you any possible tips to get more fish in your boat! I've had pretty good success with all these tactics and I'll do anything I can to pass the knowledge on. You learn more about fishing from other people than you ever can on your own!