The reason you don't look more like you siblings is because of the environment and its effects on your appearance. Also the way you get your DNA from mom and dad is how you will turn out. You will look different. This is a great wedsite will good information.
If kids don't look alike then that means there chromosomes are different. If their parents are the same they still could have gotten different chromosomes. If your parents look different then that also means they are just different and they have a different personality. Also they might be a mix mach of genes from their parents. And the environment has something to do with the way they look. This website is a great resource.
This article is about how and why you may or may not look like your siblings One example is how the sun and environment can change the way you look. If you are out in the sun more than your siblings than you will have lighter hair and most likely darker skin. You can also get different genes than your siblings. And if you grew up differently than your siblings then you will look different. If you live with your mom and your brother with your dad then when you both grow up your brother has probably changed and now looks much different than you. And if you don't eat well but your siblings do you will change and grow to look different. The reason I chose this site is because It has good information and is a reliable source.