Hiking shoes are the most important element for a successful hike.
Light clothing that covers the entire body will help you to protect your skin from sunburns, scratches and insects.
A hat and sunglasses are absolutey necessary to protect your head and eyes from sun.
It might be useful to carry a small backpack to have your hands free all the time.
Don't forget to take a proper amount of water with you. The good formula for a hot day is 0.5 liters per 5 km per person.
Pocket knife could be helpful if you're going to have a small lunch during a long hike or in an emergency situation.
For a long or difficult hike it's always better to have a specialized first aid kit.
Good map could really help you to get to the trail without hassles and easily find the way back.
Fully-charged phone is a must-have on a trail. In case of an emergency or accident, call the emergency number 112, and in case of fire call 1407.