Unlike an autosomal recessive trait, an autosomal dominant trait is not reliant on the presence of two dominant alleles. Instead, an autosomal dominant trait only requires that one of the two alleles present is dominant.  This one dominant allele, hence the name, cancels out the possibility of the recessive allele affecting the characteristics the offspring of two parents. The only characteristics  that are present are those dictated by the dominant allele.
The first characteristic of autosomal dominant traits is that the affected person’s parent is usually affected as well. For example, my dragon had eyes that rounded at the front only because at least one of his parents was the carrier of the dominant trait. The dragon’s mother had the genotype, Ee, where as the dragon’s father had the genotype, EE.
The second characteristic of autosomal dominant traits is that an affected person has a 50% chance of passing the dominant trait to their offspring. My dragon was born with the genotype Ee, making my dragon have eyes that rounded at the front only. If my dragon had a child with another dragon that was not a carrier of the dominant trait for rounded eyes at the front only, there would be a 50% chance that the offspring would also be a carrier of the dominant trait.
The third characteristic of autosomal dominant traits is that males and females are equally likely to be affected. Since autosomes do not dictate gender, both males and females have the same probability of inheriting a dominant trait from their parents.
The fourth and final characteristic of autosomal dominant traits is that dominant traits are usually seen in multiple, successive generations. Pattern is due to the fact that an offspring has a 50% chance of inhering a dominant trait from its parents. For example, if the parents of my dragon had more than one dragon, then approximately half of the dragons would be a carrier of the dominant trait for eyes that are only round in the front. The offspring that are carries also have a 50% chance of passing this trait to their offspring. Since the probability of inheriting a dominant trait is so high, it may take many generations for the trait to disappear. 
References:
Genetics primer – what is autosomal dominant i. (n.d.). Retrieved June 17, 2015, from NCHPEG website: http://www.nchpeg.org/dentistry/index.php?option=com_content&view=article&id=22&Itemid=55&limitstart=4