Walking in Scotland with its quickly-changing and vastly varying weather means that you really need to be prepared for every eventuality and you may find you have to take far more than you need just to cover all weather eventualities. The Ramblers website offers excellent practical advice on clothing, equipment and safety. The secret to enjoying walking is being comfortable. In addition to the usual gear, consider bringing along a mat or plastic sheet to sit on and pack it all into a backpack to leave your hands free.
Boots or stout walking shoes are advisable for the majority of walks. Waterproof jackets and trousers are more or less essential in Scotland at all times of year and are much more comfortable if they are made of breathable material. Several light layers of clothing are better than one heavy one as they allow more flexibility. A hat and gloves in your rucksack are always useful and if you are getting a car lift, please bring a spare pair of shoes with you to leave in the car so you can change out of your muddy boots at the end of the walk.
Denim jeans and trainers are not suitable walking attire.
Yes - the simple pleasure of a picnic stop is one of the great joys of a walk. How much you need to eat during the day only you will know but it is good to have a mixture of quick energy and slow release foods to keep you going.
Water is essential and how much you need will depend on how hot (or cold) the day is and how far and high you are walking. It is important to have sufficient water to prevent dehydration and it is best to bring it in an unbreakable bottle. The walk leader may be able to give you an indication but everyone is different.
Every walk and every person needs to take different things on a walk. To help you decide what you will need a checklist might include