Posting Bail: What you need

To break it down simply you need to prove you are not a risk to the community and that you will appear at your next court date. If you are not granted police bail at the station within 6 hours you will need to appear before the Magistrate as soon as Court is sitting next.

Ideally when you appear before the Court you will be able to explain your detention is not justified because the crown case is weak and you have never committed any serious offenses.

It is smart to try to apply for bail with the Magistrate without a lawyer initially as the process is easier. If you instruct a lawyer on the day, usually legal aid, and they are not prepared. This could result in further attempts for bail to be blocked until you have fresh material to put before the Magistrate. 

What you need before applying for bail.
1) an acceptable person who agrees to enter into a surety (sum of money).
    to be acceptable this person should not have a criminal record.
    this should be in the form of an affidavit or statutory declaration.
    The amount required will vary depending on the offense and a variety of factors.
    Anywhere from $1000 for a minor matter to $100,000 for a serious matter.
    A substantial surety exceeding $5000 assists your prospects greatly.

2) Provide a bail address so that the police can call upon you to conduct bail checks.
3) Suitable bail conditions that you agree to follow.

4) Importantly a private solicitor or barrister is your best opportunity to obtain bail as they have the
    time and resources to work on your matter and present it in the best way.