After 3 years of teaching myself German, I've decided to publish some shortcuts and tips that I've learned along the way.
1. Adjectives and Grammar - There are obviously a lot of rules in German grammar that intimidate many of the people attempting to learn the language. In English you would say "I would like the red apple", but it German it would be "Ich moechte den roten Apfel". In this example der becomes den and rot becomes roten. However, what I have found is that you can usually skip it and the audience will still understand what you're writing/saying. For example, you could simply say "Ich moechte der rote Apfel" and most would understand you. I've found that simply adding an "e" to the end of any adjective seems to work, but remember that there is no ending if the adjective is used at the end of the sentence ie: "Der Apfel ist rot".
One thing to keep in mind on this trick is that even though they understand you, adding an"e" to every adjective often results in a sentence that can be understood but still sounds wrong. However I think this shortcut is valuable because it leaves me free to learn more important things like how to properly construct a sentence, when to use du, dich, or dir and how to conjugate my verbs. One example of proper sentence construction is the translation of "I remember", which in German it would be "ich erinnere mich". There are countless examples like this where unless you know which words need to accompany the verb, your listener will be left hanging waiting for you to complete the sentence.
2. Word Gender - This is a new concept for English speakers. How can a objects like tables (in this case male - der tisch) have a sex? In English we simply use "the" for everything. The answer is, there is no logical way to do it so you have to memorize the sex (male-der, female-die, neuter-das) that goes with the word. However, every plural word I've seen uses "die". This means you could in theory always use the plural form of what you're trying to say and then in turn could always use "die". Even better, the plural form of a noun in German often doesn't even use "die" in the sentence ie: "Ich mag Aepfel". This is exactly how plural nouns function in English ie: "I eat apples."
3. Word pronunciation - My best tip here is to immerse yourself in listening to native speakers everyday. Watch TV and movies in German, listen to music in German, and try to repeat back what you hear. At first all the words will seem to run together and sound like gibberish, but eventually you'll be able to hear and separate each word. You won't understand everything right away and that is ok! After 3 years, I can listen to something and write down what was said even if I didn't already know all the words that were used. I feel that German spelling rules were easier to learn than English because they seem to have less exceptions.
4. Verbs - Verb tables are your friend! There's really no way around memorizing a lot of verbs. Fortunately most past tense forms end in "t" or "en" and most future tense forms end in "en", but there are exceptions. There's quite a few different tenses for each verb, but I've found just using the past, present and future tenses are enough. If you memorize nothing else, make sure you learn all the forms of "haben" and "werden"!
5. Ob and Wenn - They seem similar to an english speaker that's used to having only one word for "if". Here's some examples to help clarify when to use which one.
If it is going to rain by tomorrow, (I don't know yet.), i will stay at home.
(Wenn es morgen regnet (Ich weiß aber nicht, ob es morgen regnen wird), dann bleibe ich zuhause.)
By a rule of thumb i'd say, whenever you can construct a sentence by using "whether" in English, it is safe to use "ob" in German.
I don't know, whether you (will) understand this.
Ich weiß nicht, ob Du das verstehst.
6. Don't be scared to try! - Of course you'll sound horrible the first few years, but you'll NEVER improve unless you practice. Most of the German people I've met had a lot of patience and were very kind to me as I struggled to speak and understand what was said.
That's it for now, I'll post more as I think of it. :-)