Your family photographs are all about you! That means they should convey your personality and style preferences. If you're earthy and casual, stick with that. If you prefer glitz and glam, play it up. It's important to be yourself during your session, so wear something that reflects you. Word to the wise: If you wear something you'd typically never put on, you'll probably feel uncomfortable throughout your session and may not like your photos when you get them back. In saying that though, the only thing I ask is for you to wear no logos, as logos go out of date so they will detract from your timeless images.
If you would like some styling ideas, i would be more than happy to share a styling guide with you to give you a few ideas and then you can work it to suit you and your families personal style.