Bali is a safe country to visit overall. As with travelling to any destination, keep your possessions close to you at all times and use common sense when using public transport. Scammers are easy to find so stick to pre-booked taxis if you need a ride somewhere.
Many people hire scooters to get around in Bali, but this can be extremely dangerous for the inexperienced driver. Even if you’ve been driving a motorbike in your home country for years, you’ll find local rules to be very different.
It’s also worth knowing that the country has active volcanoes. If you’re staying in an area where this could be a threat – however unlikely – make yourself aware of any evacuation procedures.