Has anyone got any suggestions on how to do better with sight reading and aural tests?

A friend of mine always has difficulty in her exams when it comes to this. She's a brilliant singer but when it comes to sight reading and the aural tests, it just brings her marks down. She sings in choirs so her sight reading is usually good.
Any suggestions i can pass on to help her out?
Thanks
Angel

xx

Is there any specific part of these tests which is found difficult?

David

She tends to find picking which time period the music is from, or the deciding whether the piece is in 2 or 4 time. The rest is fine, although she finds the sight reading difficult which is unusual for her, but i put that down to nerves.

Angel