Ensure that your tyre is used for the right riding surface. For example, using a Corsa on rough roads with sharp objects increases the chances of flatting. Avoid foreign bodies in the tyre such as a thorn, staple, piece of glass or debris etc. Usually you can find the culprit if you very thoroughly run your fingers along the inside of the tyre. Glass can be embedded into a cut in a tyre and until you squeeze the tire at the cut put you cannot actually see it. Ensure your rim tape is not shifted up: Check your rim tapes, they may have shifted up to one side of the rim, thus exposing a spoke hole, or in fact creating an area where the tape can pinch the tube. Check for broken rim tape for small cracks over spoke holes, again this will pinch and puncture the tube.