Some rules to stop or prevent another financial crisis are:
Change how bakers are paid- If they are getting paid less then surely they would not take as many risks with loans. This is because, they would not want to risk anything that would cause them with getting paid even less.
Stricter rules- They could make a document where people have to sign their name for getting a loan and if they do not pay the bank back, they would get punished (for example: getting a fine that costs you more to pay back, than you took out for the loan). This can ensure that people will only take out a loan if they can definitely pay it back
Safer lending- Only giving loans to people that they know could afford it; taking less risks if they are unsure whether they can pay it back; not taking any risks if they know the person/people they are about to give it to can not pay it back.