One of the most important aspects of learning a new language is pronouncing words like a native speaker does. This does take time, but there are a few simple things you can do to improve your pronunciation dramatically.
Find a good electronic dictionary that has sound files that pronounce the words for you. That way, if you are unsure where to put the stress or how to say a vowel, you can listen and copy it. There are many such dictionaries available online.   One app you can even use on your smartphone is an app called "dictionary.com".  This app has pronunciations for thousands of English words. Listen, repeat, and listen again.  Make sure not to add extra syllables.  Tap them out with your hand, especially with words like "church", "sausage", and "finish".  This app also provides the phonetic spelling of words, so if you have learned the IPA system of spelling, you can see how to pronounce words that way.  If you have never learned IPA, it is a good idea to start!
Another good idea is to use a mirror to see what your tongue and mouth are doing when you speak. For instance, when you say the "r" sound in "car", your tongue tip should be close but NOT touching the flesh behind your two front teeth. When you say "l" as in "love", your tongue pushes and touches at that same spot. If you use a mirror to practice these sounds, you will become more aware of your own mouth and how to control it.
I also suggest learning about English stress patterns.  In English, we use stress and intonation to emphasize, to mention new information, to contrast information, and general word stress.  We use these patterns all the time.  If you don’t’ learn them, your English will sound like a robot!  Watch this tutorial on stress to improve your pronunciation dramatically!  http://www.youtube.com/watch?v=gTBNokzNQXM
 My last suggestion this month is called back-formation. Use this technique for words with three or more syllables that are hard to remember.  The word "encyclopedia, for example, has six syllables. Count them out, and start with the last one: "uh". Then add the second to last one, "ee-uh". Repeat one by one until you get "en-sai-klo-PEE-dee-uh".   This is helpful because usually the brain has the hardest time with the ends of words. If you start with the ending, it becomes much easier.
With good listening, bodily awareness, and memory skills, you can really improve your pronunciation.  It's like exercise!  No pain, no gain!!!!