Depends on your hair type, but what you can do use hair straightening gel/cream and blow dry it straight, use a heat spray and use a straightener then hair spray. Skip the gel/cream if your hair isn't THAT curly.
Use a flat iron, and maybe some hairspray if it doesn't stay. There's lots and lots of other straightening products, John Frieda 3 day straight, organix 30 day straight or straightening serum is what I use. Hope I helped!
Not to be racist or mean. But what race are you? I mean this really makes a difference. If you're African American I suggest you get a perm or flat iron it. Or if you're like me Asian then you can just use a hair straightener. That goes for any other race also.