You know, I just had this thing where I tried too hard to change my beliefs. I had the idea that it was a case of changing the core beliefs, getting them out of my brain and onto paper and replacing them for ones that would make my life perfect. The process was too overwhelming and resulted in barraging myself with all the negative perceptions I have ever had. When you come up against every negative way of percieving reality you have ever stored up you get depressed, simply because of all the negative thoughts that will swill around in your consciousness. This isnt healthy or productive.
I understand that you dont want to waste any time and the thought of simply replacing negative beliefs can be enticing so you need a natural and healthy way to evolve your belief system. Luckily, your mind will always present you with the most imminant belief to change because it is the negative thought that is on your mind right now. My advice is to not root around too much in an attempt to find beliefs but to let them surface naturally. If you have a certain area that is bothering you most you can explore your thoughts about that aspect of your life, just don't do what I did and write out all your beliefs about every aspect because it will be painful and too much to bare all at once.
Another effective method for understanding your current beliefs/perceptions is to take your goals and ask yourself questions designed to show you how you really feel about them. Think about the process of actually working towards them. What will it involve? what will it be like when I get there? Again, don't do too much at once. The best idea is to trust in yourself and know that you will be presented with what needs to change.
The best way for actually changing beliefs that I have found is to "Enquire" as Byron Katie says. Check out these links...
The Work of Byron Katie - Byron Katie International
and...
ByronKatie.com: The Official Blog for The Work of Byron Katie
Remember that the personal-development/spiritual path is fruitful but not easy. Things get effortless when you get the trick to life but it often takes a while before you really understand. I have read countless books and, although they all contained really good information, they all pointed to the same message in different ways. Sometimes things need to be explained in many different ways until you "get" it.
A good idea is to hold the intention of your beliefs and perceptions being rewired in the best way and for the greater good by a higher power (Universe/God/Source/whatever...) and then to let it happen naturally. Conscious
trying can have negative consequences.
Seriosuly, check out Byron Katie because her stuffis great.
Good luck.