No matter what language, the hardest part is to keep motivated. Sometimes you don't feel like learning, sometimes you want to give up, sometimes you can't make progress. Especially if you are learning by yourself, you have to be organized and methodic. Many people don't learn languages because of it.
@Sarah - After reading your tips I was able to distinguish the essence of the pronunciation of each word. Thank you!
@zico the best -- beach vs. bitch is a very common pronunciation challenge, especially for students from Latin America. Here is a tip to help with pronunciation:
1. When you say "beach", smile as you say it, for the entire length of the word. When you say the final "ch" sound, you should have your lips open, but pulled back, and you should be using the muscles in your cheeks--just like when you smile. The final "ch" sound should sound almost like the beginning of "Chile", but with out the "I" sound
2. When you say "bitch" (which, of course you never would! ;) ), you don't smile when you say it. Instead, push your lips out a little and drop you jaw slightly after you say "b" and keep your mouth like that through the entire word. Your mouth will only be open a little bit. The "i" sound will actually mostly feel like you're pushing air out of your throat.