When you make your vote for you candidate, you want them to truly represent what you value, and promise to fulfill and advocate for your needs. You first need to establish what those are.
Make a List
Think of what values, and goals or accomplishments you want to see achieved by the winning candidate of this election, and make a list, from most to least important criteria.
Conversely, if you know what they are, you also should make a list of both the principles and goals you would not want your ideal candidate to have.
By writing down these list(s), you are much more aware of both the qualities and goals you want to see from your candidate.
With these fresh in your mind, and on paper, you are much better equipped for selecting your candidate based on the criteria you want, using unbiased evidence to truly make the correct choice for you.