I love learning new languages, Elven is tricky because you not only have to speak it, but you have to 'feel' it; Elven should be said with feeling and spirit, never blurted out like a swear or mumbled as if it is a disgraced language.
I find having a learning partner helps a lot, so when you learn, you can practice with someone and also offer support. Plus you get a bit of fun-competition out of it.
Mixing up the simple words? Try posting some around the house..Have "I'Mar" put up for 'The Den', or for your bedroom "Rathasambe".
Though, If you still live with your parents it might be difficult to paste everything with elvish.
Try recording an elvish tape and repeat it every night. Read an elven poem or story and even work on creating your own, half the fun is 'testing'(trying to sound them out) the words, reciting it in Elven to a loved one is the other half ;)
If you don't understand the grammer that well, don't worry about it, just work on useful words (words that you can use every day like 'thank you' and 'hello') and then stick to the pre-made grammar examples. Eventually you will catch on.
The more you speak in elvish (little by little) the more you will pick up.
And yes, practice, practice, practice.
Good luck.