Maybe the distinction is more a matter of degree because we all do to some extent. I believe that you get what you are, while you are aspiring to be more - or less. Your thoughts indicate your direction, your words and actions take you there. If you are thinking thoughts of worry and lack, expect more of what you are thinking. But it really is the words you speak which release or limit your experience.
For example, Ever notice that some people talk incessantly about being sick (because they are thinking about it)? How often are they actually sick? Probably quite often. At least that has been my experience.
So try this: For the next week - 7 whole days - watch what you say! Especially, when you use the words "I am" with something following, because you are making a direct order for the experience you want. If you are observant, you will very quickly find the negatives that are poisoning your life. Just like a gardener - weed them out and replace them with life-giving words - positive words.
I have done this experiment - in our culture the rampant negativity makes it an on-going work but it gets easier and the results just get better!
Doreen Virtue did a study of the frequency of words and found that there is a major difference between negative an positive words and their frequency. Dr. Emoto also has investigated the effect that words and intentions have on water molecules. You can find both on the web but here are some links.
Visual Evidence of How Words Can Be Angels in Your Life by Doreen Virtue, Grant Virtue. http://www.hayhouse.com/angel-words
Dr. Emoto How Frequency/Words can change matter http://www.youtube.com/watch?v=iu9P167HLsw