Breathe, prepare, research! Once you have taken a deep breath research the business as whatever product or service u may be selling or doing. Then get your clothes ready, fill the bath with bubbles ad relax.
Try your best, extend answers eg, "my name is x and I live in x with my children and husband" that just won't cut it, elaborate... Eg, "my name is x, I live in x with my x children and husband. In my free time I like to x, x and x with x I have a passion for x and x( use the first x to big up that you are interested in te job by using what u researched you will be selling/doing)."
Beware of what your weak points are, expect that as a question and turn it around, something like "my IT skills need improvement but I have bought a typing skills book to help me improve on this" it shows you are looking to improve yourself.
And after all that, be yourself. Personality is everything! Smile and greet them when they ask you to enter the interview room. Maybe even extend your hand to shake because te first 30 seconds are the most important, oh and introduce yourself as soon as you see them too.
Best of luck hun! Be you and I'm sure you will do great! Xoxo