Ingredients

1 cucumber
2 sticks of celery
a few big handfuls of leafy greens (eg romaine lettuce, spinach or kale)
1 apple (optional if you prefer without fruit)
½ lemon or lime (without peel) 
small piece of ginger
a couple of florets of broccoli
clove of garlic (optional)

Cucumbers and apples are both hydrating and great for cleansing the body. Celery reduces acidity, kale and green leafy veg are full of minerals and high in chlorophyll which boosts energy. Ginger is a natural anti-biotic and decongestant. Lemon and garlic both have antibacterial properties and are great for cleansing the liver and intestines. Broccoli is packed with anti-oxidants and high levels of calcium and vitamin C
 

Top Tips

For a zingy alternative, add a little of the peel (of either the lemon or lime) 

If you are trying to drink green juices without any fruit, start with milder greens (eg spinach, romaine lettuce) and add more lemon & lime juice.

If you don't own a juicer but have a liquidizer then a great tip for making this juice is to use a nylon nut bag.  Simply blend everything you want to include with a little added water and strain it all through the bag.  Juices made this way are likely to oxidise quickly so best to drink it straight away.  This is a quick, cheap and cost-effective way to get started juicing.