Totally not an easy task. You could eyeball it. But it takes a long time to manually compare your desired font to those you think it might be. The easy way out -- the method I suggest -- is a font recognition service like WhatTheFont. It's is an online application that recognizes and tries to match an existing font.

All you need to do is upload a scanned image of your font and the app compares it against images in its data_base_ in search of a match. Also a pretty good forum, tips, etc.