Two portions of bread/potatoes/cereal: Alternate between wholegrain and wholemeal breads depending on preferences and use different toppings. Or try crackers and popcorn.
One portion of meat or fish: This can alternate between a slice of ham, an egg or many children now eat tuna and sweetcorn. For vegetarian parents a tofu or bean supplement can be used here.
One portion of milk and dairy: This could be a yoghurt, cheese or milk and alternate regularly.
One portion of fruit: This can be either fruit juice or a piece of fruit or tomato. Some of the tricks with fruit are to try to keep it as fresh as possible and prevent it from getting battered as this turns children off. Try wrapping fruit in foam so it doesn't bruise.