Hijab should meet the following conditions:

1. The clothes must cover the whole body, only the hand and face can be seen. But according to some schools of Fiqh, the face must also be covered (Niqab).

2. The fabric must not be so thin that you can see through.

3. The clothes must be loose fitting, the body shape must not be emphasized.

4. Women's clothing must not resemble men's clothing.

5. The design of the woman's dress must not resemble the dress of an unbelieving woman.

6. The clothing must not consist of challenging or ornate designs that attract attention.

7. One should not dress in certain clothes with the intention of standing out among people or trying to mark one's status by wearing precious chains.

"Say to the believing women that they should lower their gazes and restrain their sensuality and not show more of their pleasures than what can [properly] be visible" (Qur'an 24:31)
"Say to the believing men that they should lower their gaze and restrain their sensuality; that leads to greater purity in their lives. God is aware of what they do" (Qur'an 24:30)