Don't give up--my bindings used to be crammed together at the ends, lumpy with too much fabric, etc. Then a dear friend showed me how to do it properly so it fit just exactly right and I've never had a problem with it again--easy to do once you've got it down. She made me a practice sandwich with practice strips attached and wrote down the directions exactly. PM me and I'll do the same for you (paying it forward).
Don't waste your money on that plastic binding "tool". When I was struggling to figure out how to end binding I bought this and now just use it for a small straight-edge.
Dana