Most aneurysms are caused by high blood pressure that weakens the artery walls so one way of preventing aneurysms is to lower your blood pressure and keep your blood pressure in check.
Trauma to the brain can also cause a brain aneurysm as well and if you do have a brain aneurysm you need to seek medical attention right away because if it ruptures the brain aneurysm can kill you.
If someone in your family has suffered from a brain aneurysm then there is a likely chance that you could suffer from a brain aneurysm as well.
Most brain aneurysms come on without warning so you may not really know for sure if you're about to have an aneurysm or not but if you think you or someone is about to have a brain aneurysm you need medical attention right away.