All you preparation will be in vain if you are not fishing where there are flathead. Take time to survey potential fishing areas to find submerged timber, underwater creek channels, logjams, or other suitable cover for flathead. The best habitat will support the most and largest flathead.

After you have found a good potential site you must decide the best spot to anchor your boat or fish it from shore. I fish from shore so I then find a flat area where I can fight fish in total darkness. I remove all trip hazards and vegetation that might hang up my line. I may remove overhanging limbs that inhibit casting and hook setting.

For more about site selection see this article.
Hunting trophy flathead

Whether you catch, seine, or buy your live bait, it is essential that you keep it as lively as possible. You will probaly need an aerated bait container or recirculating livewell to keep baits healthy. Cooler water lowers fish respiration and holds dissolved oxygen better. If you cool baits water with ice be sure to temper the baitwell with lake temperature water slowly bringing baitwater temperature to lake temperature. Casting baits from cold water in baitwells to much warmer lake water will put them in shock and may kill them. Avoid crowding baitfish and provide large containers. Different baits require different levels of care. I do not put other baits with goldfish because they die quickly.

Check your baits regularly and replace water often. Recirculation is best but aerated buckets need water changes to flush amonia from water. Amonia developes from fish urine as they foul the water.

Use the smallest hooks necessary for your target fish to minimize stress to your baits. Hook your baits in non vital areas.

This is an area where many catmen can improve. During winter rods are physically checked for cracks or damage to reel seats and cleaned. Guides can be checked with q-tips, cotton balls or old pieces of pantyhose to insure there are no sharp edges or burrs that could damage line.

Reels should be cleaned and lubricated. Lubrication should be lighter oil if you commonly fish in cold weather. Drag disks replaced if necessary. New line should be spooled. Drag should be readjusted before fishing. Drag disks swell and contract as they get wet and then dry out. Check the drag to make sure dirt doesn’t cause the disks to stick.

I set drags light. Rain or heavy dew may cause drag disks to swell and I always have the option to tighten drag while fighting fish. More often I use my thumb to apply more drag when I feel necessary.

When re-assembling reels put a dab of Loctite removable (blue) thread locker or clear fingernail polish on screws. This will prevent them from accidently working loose.

Before each fishing trip your rod and reel should be inspected to guarantee trouble free operation and flawless function. Dirt in levelwind worm gears can cause malfunction of levelwinds. The level wind pawls are made of soft metal to act as shear points. This safety feature means that they will also wear fast. Most are adjustable but at some point they will wear and malfunction. Make sure line is through all the eyes of the rod. Visual inspection of the line to determine if there are nicks or frays. Excess memory coils indicate old line and possibly weak line.

I inspect the last 2 feet of line for weakness when I examine the hook. If I suspect a problem I cut off the last 2 feet of line and retie. Then I look at my knot. If it looks bad or I see rust on the hook eye I cut the line off and retie. If I see a knot in the line that is not supposed to be there I cut the line above the knot and retie. Live bait or casting can often put an overhand knot in your line.

I then inspect my hook. If it looks weak or bent, I replace it. I always sharpen hooks till they will dig into a thumbnail before fishing. Hooks that I used previously often have the finish worn off from current of baitfish movement. I check the eyes for signs of rust that may weaken my line. Previously sharpened points will have the finish removed and must be touched up to get them as sharp as possible.

I sharpen new hooks I put on. New hooks can be made sharper. The finish applied to new hooks prevents corrrosion. But it tends to round the point.

For some rigging options check this link.
Rigging

Organize your fishing area. You should be fishing in the dark so keep your boat or bank area clear so nothing can interfere with fighting fish. Have nets and other necessary equipment placed where they are out of the way but close enough to reach when needed.

If you bank spot is sand, remember that sand in reel gears will lock them up. This becomes very important during hard rains that spalsh sand into reels. A reel that is out of gear will get pulled into the water by a cat before line releases once sand has splashed into the gearing.
If you suspect rain is coming and you are fishing on sand consider laying rods and reels on a tarp or plastic bag to keep sand out. Two forked sticks will hold a rod and reel up and keep sand out also.

If a sudden storm comes up and you check your reel and sand has locked it up, don't despair. Penn reels has loose gearing and fit. You can dip them in the water or pour water on while turning the reel and sand will often work itself free. Other reels with tighter fits will take more time and water to loosen back up. If a reel fails to go into freespool because of sand I reel it in. Better to use one less reel than risk it being pulled in by a big cat.

If you are fishing with someone you should discuss your plans for fighting and landing fish so there is no confusion during the battle. You should have time to agree on strategies and tactics before the excitement of catching and landing fish.

Our tactics include wearing big flathead out with drag. If we go out in a boat to minimize potential snags in some areas we want the other catmen with us to understand the risks and rewards of the manuvers.

If the area is clear to land fish from bank we will point out the best area to land a big fish. It must be deep enough to get the net under the fish and clear of rocks and brush that can tangle the net.

We also discuss that the guy fighting the fish will tell someone when the fish is ready to net. Swinging a net in the dark often results in lost fish. The man fighting the fish has the best idea of how tired the cat is and if it can be safely netted.

If we have a new man we also mention that lifting large flathead by the net handle will likely result in a broken net. We instruct him to grab the hoop after the fish is in the net.

You also need to have a plan if you want to release fish. Handle the big cat as carefully as possible. This is hard because they rarely cooperate.

Having a large landing net takes some of the stress off of the fish and the fisherman. Use the net or a weigh sling to keep fish calm when weighing.

Return the fish into water and hold by the tail. It will revive in a matter of minutes. When you can feel it struggling against your hand it will be strong enough to release.