Start off by looking at the whole plot. Some of it can be changed for the better.
Wise Old Mentor sounds cliche. If you really want to draw the reader in, do less of the Cliche stuff. Go for something out of the box.
Maybe the Old Mentor has a drinking problem, and so the only time he is actually wise, is when he is Sober. However, maybe when he is Sober he is also very mean.
Cut the wise out of his title. Make him just "Old Mentor". Or Stick his name after his Title. If his name was Bob, call him "Old Mentor Bob."
Anyway, when it comes to starting, remember:
Show don't tell.
Don't tell us about the characters. Show them to us by thier actions.
Want to start a story? Brainstorm different ideas. Do you want the story to open with the hero being ordered to do chores?
Maybe he is getting up, and readying himself for another day with the old man.
Or maybe you can start with the old man looking to fix himself something, only to find that there is insufficient wood in the stove, and so he wakens the hero and asks him to fetch firewood?
I hope my suggestions are of help.