Traditionally Democrats are liberals and believe in large governments that are more involved in our daily lives. They believe in the “greater good” and people being more equal rather than the emphasis on the individual. They believe in as many social programs as the government can create. They are more pro-choice and more pro gay marriage.
Republicans are generally more conservative. They believe in much smaller government and much less government interference in daily life. They believe in the individual and individual rights rather than welfare for all. They tend to be more religious and thus have problems with gay rights and abortion. They tend to follow the words of the founding fathers and the constitution more closely when making decisions.
Hope this helps you a little.