Either by leisurely building it up with nominal tricks or pulling off a single trick combo that satisfies 3000 or more points. Each skater has an arsenal of 3 signature moves. Except Tony Hawk who has 4. It depends on the skater, and some signature moves are suited to a character's stats. I'd estimate, that if a skater excels in air, that individual might know a move that requires grand air to accomplish.
All signature moves distribute ample point values that easily surpass regular moves.
Its difficult to universalize when it is best to use them. Take notice to what style of trick it is, then treat it accordingly to the suggestions given on that trick set. Try to fit these moves into a combo if, and whenever possible.