It is always a good idea to have a map of the trail you will be hiking. Often when I am hiking I will come to a spot where the trail is not well marked and I am not sure which way to turn. I have turned the wrong way and walked for a while before I realized I needed to head back.
There are a couple of places you can go to get a map of your trail. Trailmeister is a good resource to print your trail map and get a trip report in the process. This enables you to have your map on hand while on the trail to look at and see where the trail heads and how much further you need to go.
You can also go to the ranger station closest to your destination. They often have trail maps printed for free of the local trails in the area.
If you feel like spending some money, you can buy detailed maps of your trails or even books that include many different trail maps online, at your local bookstore, or even at the ranger station.