Whenever I have modeled characters after people I know, it either doesn’t work or it turns out to be a time consuming struggle to forge an independent identity for those characters. So, I have learned to create a character who is physically and mentally very different than my primary model, then layer in attributes of a medley of real people (little habits, speech patterns, biases, profession, dog, favorite food, love of _______). I do a lot of research and will include snippets of dialog, such as professional or regional lingo, to add realism.
Think of it as the Frankenstein Approach.