It is in meat, eggs and dairy products and you also make some cholesterol yourself.
Eat fewer eggs (<3/week) and less dairy products e.g. cheese, cream.
Replace butter with olive oil and mono-unsaturated margarine (e.g. based on rape-seed or olive oil).
Eat less red meat (replace lamb, pork, beef with poultry).
Eat more fish, including at least one portion of oily fish per week (e.g. mackerel, herring, kipper, pilchard, sardine, salmon or trout).
Certain margarines can cut your cholesterol level down but can be quite expensive.