If you want to learn German and you are an English speaker, especially American, my tip:
Never speak English to them. Never.
American English is the Neu-Neuhochdeutch. It is like, aber superhammerf***inggeil!
You will get to learn humility by shedding a lot of your personality by learning to communicate in way in which much of your personality will go to the wayside.
Get a decent grammar; you Mormons are known for your language dominance, so I bet this could be helpful:http://www.amazon.com/Hammers-German-Grammar-Martin-Durrell/dp/0071396543
Start with a good English to German dictionary for a while:http://www.amazon.com/Collins-Unabridged-Dictionary-Harpercollins-Dictionaries/dp/0060733810
Then as soon as possible get a German dictionary for non-native speakers:
EDIT: (I prefer this to the Duden):http://www.amazon.com/Langenscheidt-Gro%C3%9Fw%C3%B6rterbuch-Deutsch-als-Fremdsprache/dp/3468490372http://www.amazon.de/Duden-W%C3%B6rterbuch-Deutsch-Fremdsprache-Nichtmuttersprachler/dp/3411705116
These are my recommendations.
Watch every crummy American TV show dubbed that you can. The obvious and familiar nature of the shows will let you soak up the German, don't watch it with dictionary. Just let it sink in.
Every German University offers for nil German for foreign speakers classes from "nur Bahnhof" to Ueber-Oberstufe. Make use of them.
Never speak English with Germans. They will try to constantly do it, because they want to practice their English language skills especially the American vernacular.
Don't let yourself end up in an "English speaking ghetto".
And as soon as you start getting your head around German, start using:http://de.wikipedia.org/wiki/Wikipedia:Hauptseite
For your wiki stuff, then read the English articles. It will broaden your language skills and knowledge as well. The articles in German will often have infos the English articles do not.
I spent time in the German-Speaking world. For the first six months, I did not read, write, speak, or intentionally hear a word of English. I then was able to enroll in University and got by very well.
And on how to use a dictionary: sparingly. Read, listen, absorb. Go to the dictionary only to make sense of what you cannot possibly understand.
Hammer's Grammer will help enormously to increase your vocabulary by its thorough treatment of verbal prefixes.