Creating Fictional Characters

I've written a few stories based heavily on personal experience and I think they speak to me, anyhow, and help me remember the events upon which they are based.  But I find trying to portray a fictional character hugely difficult.  I mean, sometimes I can feel a character I write for a little bit, but they always escape me and become dry as straw.  My characters are written stickmen. 

Authors tell me that they make up characters based on someone they knew, or by piecing together mannerisms from various people they knew. I can't do that.  Maybe there has not been enough variety in the people I've known in order to find one to fit my plot.  Perhaps my knowledge of the people I've known has always been rather shallow.  I think I'd even have trouble picking out a salient characteristic adjective to describe most people.  I've written down lists of adjectives that I think would describe a character, but I've got no idea how to transform those adjectives into characters.  The only way I'll ever be able to do it is to take note of how other writers make characters and try to imitate them.  And I've got some catching up to do there, because I didn't enjoy reading any fiction until, like, the last 10 years.   Something tells me I'm decades behind in my reading.  Maybe by the time I die, I'll be widely read enough to make up a character.  Fuckin' forsooth.