Geting the Current from the batteries to the trolling motor can sometimes get a little tricky.  There are many different ways to accomplish this.  Todays higher thrust trolling motors should be wired with a minimum of a number 6 stranded wire cable.  An appropriate bow plug (if bowmount) and breaker at the battery should be used. Today's trolling motors can draw up to 55A when on a high setting.  The wire, and breaker, must be able to carry this type amp draw. The breaker is used to protect the wiring.  Using smaller gauge (higer number) wire with a breaker that is rated at trolling motor draw could result in melted/burned wiring.  This is why it is important to match the wiring, breaker, and trolling motor amp draw for Maximum efficiency. 

If you are "hardwiring" or not using a plug, then an appropriate terminal block will make for a clean install.  Some "standard" wiring diagrams are:

 24/36V--Jumped at the batteries:

 24V------Standard Boat wiring using "Marinco" style plug: 

 12/24/36V--Standard Boat wiring  4-prong "Marinco" style plug: 

 12/24V--Standard Boat wiring using 3-prong plug:

 12/24V--Using a 3-position, double pole charge/run switch

 Basic Switch Wiring Diagrams