The first step to a successful and safe (non-group) walking experience in the mountains of Madeira Island is ...
The level of planning required depends on factors such as weather forecast, experience, the route, etc. Always plan for the best ... take with you the essentials, and know your limits. This applies not only to mountain walking but also when you want to walk a Levada on Madeira Island.
Anticipate also for a situation whereby something may not go as planned. Think of the worst case scenario that you need to be rescued from the mountain or deep in the valley. Always (I repeat: always!) leave some basic information with someone (the Emergency Point of Contact), containing basic details of your route and fellow walkers. This can reduce the time take for emergency services to deal with a situation, should one arise. No one goes out for a day's walking with the intention of being rescued, but it can happen. Be prepared.
Experience and Limits
Know and recognize everyone's limits and plan a route that is appropriate for the experience, and skills of you and your walking partner. Mountains have demands that people may not be used to. Do not put yourself and other people's safety at risk.
Plan your route and write it down. Check whether the distance and difficulty of the route is appropriate for you and your walking partner. Check with the Madeira Tourism Board if there are any access restrictions. Tip: email the route to a designated Emergency Point of Contact.
The weather can play a huge part in the day's success and your safety on the mountain or Levada walk. Check the forecast and be realistic about whether the intended route is appropriate given the forecast. Temperature can drop as you get higher, it can suddenly be very misty or winds become much stronger, making it very chill.
Again if things go bad, you need to have a plan, and that plan should be prepared before you leave your accommodation or home. Know how to call for help and what information you should leave with a designated Emergency Point of Contact (EPOC). Consider also how you will call for help in remote areas where there is no mobile signal. If things go wrong and your need to be rescued off the mountain, your plans that you left with your EPOC will be very important information for the emergency services.
Take the appropriate clothing when going to the mountains or higher planes of the island. It can be surprisingly colder than the lower coast areas of the island.
Aside from clothing there are some other items that you most not be without, such as: map and compass, survival bag and a torch ... yes, even in summer. These items are of primary importance when planning your day and safety considerations for the walking experience.
Food and Drink
You will be using more energy walking than sitting watching TV. Take some (healthy) food appropriate to the route and energy requirements. Also sufficient water for the day.
Always have a first aid kit with you which will allow you to deal with unforeseen situations.
Enjoy the walking experience and always remember the walkers code ... Respect the nature and leave no trace behind!