Do you stop to take the time to reflect on what you're thinking about? Do we take the time to consider that our thoughts affect our action?
What are your thoughts telling you? Are they telling you that the task ahead is too hard or that you don't have the talent or skills to achieve your goals? Are they telling you that you're too tired/lazy/good-for-nothing to continue on this road or that failing is more likely to occur than succeeding?
Believe it or not, your thoughts can be a greater hindrance to your success than lack of ability or people trying to prevent you from reaching your goals. If you think that you can't--no matter how valid your reasoning is--you won't. Period. However, if you allow yourself the chance to try, whatever it may be, you're giving yourself the chance to be pleasantly surprised by the results.
What have you been telling yourself that you can't do lately? What if you permitted yourself to believe that you could do it? What steps would you take to make it happen if you thought you could do it? Why not try that today. Say to yourself, "If I wanted to achieve [insert your goal here], what do I need to do to do this?"
If your thoughts tend to have a negative spin, change them. Allow yourself to believe that you can, and watch how things begin to change in your actions and in your outlook towards yourself.
What are you thinking?
"For as he thinketh in his heart, so is he..." (Proverbs 23:7a KJV)
"Finally, brothers and sisters, whatever is true, whatever is worthy of respect, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if something is excellent or praiseworthy, think about these things." (Phillipians 4:8 .NET)