1: Buy in advance
Train tickets go on sale 12 weeks ahead of schedule, but flights and coach tickets can be bought much earlier.
2: Check for sales
For example, National Express's 40,000 £1 seats last year, or Ryanair's sales that include all taxes and charges (a significant saving), and Virgin's 2010 £5 seat sale.
3: For airlines, check sites that scour other online ticket agents.
Then go back to the cheapest airline to see if booking there isn't cheaper still.
4: Book as a group when travelling on trains.
With Virgin Trains, for example, the third passenger in a group of three to eight will receive a disount of 10% if the first two adults pay an advance fare.
5: Railcards are not only for the young or pensioners.
The National Rail Family and Friends card, for example, gives discounts for up to four adults and four children.