Any change to a mole as mentioned above is the most important thing but other risk factors include living abroad, episodes of sun burn when younger, working outside, keen sportsperson (golf, sailing, surfing, windsurfing, tennis, cricket, etc) and a family history of skin cancer.
If you live in East Grinstead, Haywards Heath, Brighton, Hove, Tunbridge Wells, Worthing, Hastings, Eastbourne, Chichester, Sevenoaks, Horsham, Bexhill, Crawley, Caterham, Guildford, Horley, Maidstone, Channel Islands or London, Mr Banwell would be delighted to see you for rapid assessment and diagnosis.