Compost is free! Addition of compost to the soil reduces or removes the need for expensive and dubious chemical additives.  

When compost is added to your soil, this encourages earthworms and other beneficial organisms. These break down the soil causing nutrients to be released

How to Make Good Compost

LET AIR CIRCULATE INSIDE THE COMPOST BIN OR HEAP

The key to making a good compost bin or heap is to use a mixture of finer materials (grass clippings, leaves etc.) and coarser materials (shrub clippings, straw etc.). This mixture prevents the heap from compacting which prevents sufficient air circulation.

Regular turning of the compost bin (once or twice a month). This involves taking a fork to the heap and mixing up the contents. This introduces air into the compost which speeds up the composting process.  

SUFFICIENT MOISTURE

The micro-organisms in the compost bin and heap need moisture in order to do their work of breaking up the contents of the compost heap. Normally, the finer materials in the compost heap provide enough moisture, but if a lot of coarser materials are used, it may be necessary to apply a small amount of water infrequently. Straw, in particular can cause a compost heap to become too dry, so water the straw before adding it to the heap. Don't let the heap become water-logged though, this is worse than too little water.

FOOD FOR THE MICRO-ORGANISMS!

Not surprisingly, the micro-organisms in the compost need food if they are to rot down the heap and turn it into compost. These ingredients are called compost activators. Green compost (grass cuttings, leaves etc.) provide a good amount of food, although the addition of bone meal, animal manure, or similar will speed the process composting process considerably.

HEAT

Garden waste will only turn to compost if there is sufficient heat. Within limits, the higher the temperature of the compost heap, the quicker it will become usable. The peak temperature of a compost heap is 60C (140F), at this temperature, it will compost quickly and destroy weed seeds.

You can help the heap to achieve this temperature first by making it a decent size - the larger the compost heap, the higher will be its temperature. A meter (3 feet) square, by a meter high is ideal.  Where the heap contains adequate water, cover it over the top with a plastic sheet for a week or so.