Your equipment should be prepared for all possible weather situations. The weather changes very quickly and sometimes the weather can change several times during a single hike. So always have something warm and a rain jacket with you, also of course good shoes. It is also advisable to think about sun protection. Along many levadas you have to cross tunnels, some are short, but sometimes they are very long, more than 2km. For this you should have a torch or a headlamp with you (if necessary, you can also use the torch function of your mobile phone). Bring enough food and water, because most of the time you will not find any kind of facilities.
In general, most of the hiking trails are good and regularly maintained. However, you should always be very careful. Especially when you are taking pictures. You should always be careful where you walk. Often roots or stones protrude from the path and sometimes the edge is hidden by leaves. Even if you would like to enjoy the view while walking, you can better stop and enjoy the view in peace.