First you should forget all of your ethical principles and start from scratch. Ultimately our ethical principles decide our politics and more often than not the principles we hold to are the ones that were passed down to us. More often than not they are well intentioned but misinformed. Most people want to do the write thing, ethics are something most people believe they understand even if they have never made an effort to study them. Thankfully it's not that hard to get a cursory understanding of a variety of ethical principles, you don't need a degree in ethics to appreciate the values of different ethical systems. Read over the wikipedia ethics page and further explore the ones that most appeal to you. Utilitarianism is a great place to start even though it has its flaws.

Then expand your political horizons. Learn as much as you can about political ideologies that are radically different from your own. Anarchism, fascism, socialism, capitalism, liberal democracy, parliamentary government, etc. Each has its benefits and its drawbacks. There is no perfect system, ultimately the choice comes down to which set of problems you are most willing to deal with.

Try to maintain an open mind, you should be able to entertain an idea as though you believed it was true even if you do not. For example, when examining fascism you should base your examination on the premise that national unity is paramount above all else. Fascism was not a dirty word until WWII, it was just another political ideology, so when learning and thinking about fascism it's important to push aside preconceptions.

When learning about political ideologies you also need to familiarize yourself with the social, political, and economic critiques and analysis that they offer. That includes factual research. There's a ton on information available on the net in easily digestible forms but you'll need to watch out for those with a specific agenda to confuse or misinform. Sometimes that kind of misinformation is not intentional. This is most visible when talking about leftist ideologies. For example, socialism has become a dirty word in the USA. Its meaning and definition do not at all match the colloquial perception of it yet the basic underlying principle is quite simple. Instead of a boss who decides things for the employees, the employees elect a manager and collectively make business decisions themselves. That's socialism in a nutshell but there are countless different forms of socialism.

Remember that every state institution (not state as in Colorado, the State as a political entity) has a vested interest in promoting and justifying its own existence. Sometimes this is good, more often than not it is bad. As you learn and think about politics you must be very wary because the loudest and most easily heard voices are those that are most likely to deceive you.

Once you've got some ethical principles that you believe are worth believing then you can compare them to the ideologies you have learned about. For example, if you believe individual liberty is paramount then anarchism might be for you. If you believe that most people are not competent to make political decisions themselves then liberal democracy might be for you. Sometimes compromises must be made. For example do you want to promote liberty or security? These are often at odds though a balance can be found.

After you've settled on the political ideology that seems best you absolutely must learn the strongest arguments against what you believe. Political and ethical positions are only as strong as their ability to withstand the harshest criticism. If your beliefs can withstand the strongest arguments against them then you're done. You've found your own political platform and you are most able to defend it against those who would challenge what you believe.

tl;dr: Anyone can make a list of things that they support but to find a strong political platform for yourself you must make a conscious effort to learn about as many alternatives as you can find. If you half ass your political beliefs then they won't be worth anything at all.