For instance I know with my boat a 190tw tracker with a 90hp mercury fully loaded I can troll at 2.5mph yet if I fill the live well to capacity it will slow me down to 2.2mph if I drop the trolling motor it will slow me down to 1.6 mph ( all speeds on the Sonar ) Knowing that information allows me to adjust speed very easily by removing some water from the well or lifting the trolling motor or any combination of those, I will even add weight to the boat before leaving the house or degrease weight depending on wind conditions. You have to play with your boat and weight. I also have employed a sock or bucket if needed.
After learning the speeds of the boat the next thing I want to do is find the sweet spots on the boat for setting rod holders. For my boat I have one right next to the steering wheel and one across from it and two more up near the bow. The bow mounts are for use when I’m on the electric trolling motor or running planer boards and the other two are for when I’m on the big motor mostly. The third is dead center of the boat behind the middle passenger seat. The center holder is for a pure flat line that runs on the surface normally floating fly line and a fly on it.
Next is learning the lures! Some lures work well others work great. The Berkley Flicker shad and Rapala SR series are my two favorite baits for trolling as they run true and are easy to figure depth accurately. Not all baits dive as advertised on the package and you must learn where they will run with the line you are using and how much line out.
Finally the reels used are very important. For starters I suggest a good line counter reel as it will aid you in learning how much line out. As you progress and gain knowledge you can switch to spinning gear. Spinning gear you need to learn to count at a constant steady count each time. I see many people stop the line going out way to soon, even when with me I have to tell people repeatedly to not flip the bail until I tell them. It is a paranoid thought they are letting to much out and won’t be able to fight a fish on a long run. Trolling reels should hold at least 200 yards of line and letting out 150 feet is nothing to worry about.
Those are the pure basics. Now how do you ( know ) what each will do? This is where time on the water is vital. Find a long flat with a known depth. Set out a buoy marker at one end and maintain a constant depth lets use 20 feet of water. Maintain that depth for at least 500 yards or more when you start getting out of that depth drop the other buoy. Now you will want to start trolling the baits.
Make a pass with no baits in the water buoy to buoy and write down your speed. Then fill the live well and do it again writing the speed, next is to do it with the trolling motor down. Play with different ways of weighting down your boat and removing weight and write it all down.
Next is to put out the bait I suggest doing this without hooks as you are trying to learn the depth of the bait. Doing the same procedure as listed above let the bait out slowly until it starts barely hitting the bottom and mark that amount of line on your note book along with the speed of the boat. Then let out more until the rod tip is bouncing hard, this will show you the information to write down for when a bait is barely hitting bottom and when its slamming the bottom. Make numerous passes on that line buoy to buoy playing with speeds and line out distances. Do this for multiple depths starting at 6 feet of water and run it all the way out to 25 feet of water. It can take you most the day playing with all types of factors from lure to boat speed and line out and wind conditions.
When you have all that done you will know where your baits run with a high degree of confidence. I try to learn at minimum of 10 baits so I have a good arsenal. Flicker Shad for instance I have learned the entire series; color I do not worry about it’s the bait itself you need to learn.
After all that you are ready to start trolling. I talk to many people who think it is a matter of putting baits out and start motoring and hope a fish jumps on the line. Sure anyone can do that but it’s pure luck if they hook up. Just like a bass fisherman working over a point for bass that takes his time and methodically picks the area apart a troller must be able to do the same thing. Both are specialty fishing techniques.
Knowing your species is the next important key element, some species prefer to align themselves in different position depending on current of the water. Wind creates a current as does generation and paying attention to those factors will help you increase your catch. Many days I have caught fish trolling in a certain direction but not another. If you are catching fish for instance trolling south but come across the same area going north and get no bites I will run the south troll and at the end of it reel in make a wide birth of the pattern and run to the starting point again and maintain that south pattern until it stops paying off.
A quality depth finder will pay off high jackpots especially those with side scan technology. First thing they do is show you where the fish and bait is concentrated on the up/down but typically threadfin shad prefer open water and this is when sidescan shines as you can quickly locate the area they are in. I try to never run over the top of the bait but set up a pattern that enables me to troll past the outside of the school. This is a guess as bait moves and where keeping an eye on the water will help as many times you can see the bait on the surface. When you see the bait try and miss the school by at least 30 feet to one side or the other of it so your bait is the one that got separated, this normally triggers a bite.
Speaking of triggering a bite; early morning you want to troll fast ( again knowing your species ). Using walleye for an example, early in the morning they will be shallow typically but as the sun comes up they go deeper. I like to speed troll 2.5mp up to even 3.0 mph. I am looking for aggressive fish and speed trolling triggers some of the most aggressive bites and some of the biggest fish. As the day progresses on slow down till you find the speed they want or your target species wants to be specific.
Mark on your GPS where you catch each fish, if you catch two from the same spot stop the boat and work the area over with a soft plastic or crank bait you may have found a holding point and multiple fish can be had here. I have caught many smallmouth and walleye by doing this, as trolling is not just a fishing technique but a fish finding technique.
The last thing I want to talk about is extreme precision trolling. This requires two people to do it and is most effective on long points. You need one person on the big motor one on the bow mount trolling motor. As you troll out a point keeping a close watch on your depth finder if it moves more than a few inches of bottom depth have the guy on the front kick the bow so the boat maintains that depth the guy on the big motor does the same. This is also a very good way for sweeping points where you intentionally are making a tight turn across the tip of the point to run the baits in a sweeping motion to hit fish that might be in a pocket.
In closing I know this is just simple basics to help people start trolling. If you get the old mentality of you have to be casting all the time to catch fish out of your mind and understand trolling is a very specific and precise control of the boat and baits you will have put a new trick in your fish catching arsenal. It takes time to learn just like any other type of fishing and it can be frustrating just like other types but it will cover more water than other types quickly and help locate aggressive feeding fish you may have otherwise missed. Good Luck