I really need to work on just relationships with people and all. Naturally, I have a mad looking face so it's pretty hard for me to force a smile. When I'm talking to girls, I don't think I make them feel comfortable enough and come off as a little bit mean/assholeish. I also have a low voice and mummble sometimes. Like most of the time, it just ends up with girls just getting mad at me or being offended or something. I'm not really sure how to describe the whole ordeal myself. Any input is appreciated.

actually me and my friend are kind of like that
well i was but my friend still is
because we are mexican our faces look naturally angry
well at least for me and my mexican friends it looks like it
i got out of the habit
when you walk by women or anyone in general, raise ur eyebrows (both) and give a half smile if you get what i am saying, (its kinda like someone said something a little bit funny and you gave it a little chuckle instead of a big laughing smile)
and keep practicing that
your face muscles get used to it and ur face gets a little less tense looking
and thats a start

and as weird as it sounds but just go to a mirror when ur home and practice smiling
it sounds dumb but it works your face muscles and BAM! ur a happy lookin guy lol