Choose the best quality, freshest vegetables and fruit – slightly under-ripe is best.
Be fussy about sterilising jars and lids. The jars should be hot when the hot preserve is poured into them.
Stand marmalades and some jams after cooking to allow the fruit to settle and disperse through the syrup before bottling.
Fill the jars to the top with the preserve; it will shrink slightly on cooling, leaving a small space between the lid and the surface of the preserve.
Only make small amounts of jam at a time. The overall quality and clarity will be better.