For Non RVSM airspaces:
From transition level to FL290 - every 1000ft is a FL. Eg. 260,270,280...
From FL290 upwards - every 2000ft is a FL. Eg. FL 310, FL330, FL350...
For RVSM airspaces:
From transition level to FL290 - every 1000ft is a FL. Eg. 260,270,280...
From FL290 to FL 410 - every 1000ft is a FL. Eg. FL 300, FL310, FL320...
From FL410 upwards - every 2000ft is a FL. Eg. FL 430, FL450, FL470...
Are you giving the July attempt? When is your exam?