FIND GOOD PRODUCTION, because the first thing people usually pick up on is how a song sounds. Having solid production can turn almost any song into a media sensation. Poker Face's instrumentation is very strong, very catchy and has a lot of variation in it.
CREATE A GOOD SONG CONCEPT. Poke Face does this and more by using the concept of a poker face as a metaphor for sexuality and deception. Songs with thought behind them tend to have a lot more staying power than their competitors.
WRITE A CATCHY HOOK. This is critical to making a hit song, because the chorus, or the hook, is usually the first part of the song that people memorize. In the case of Poker Face, the hook is catchy because of the stutter-like manner in which it is delivered.
HAVE STRONG LYRICS. Strong songwriting is mostly to appease musical critics. Most pop music fans could careless about the words in the song, as long as they are catchy. Lady Gaga's lyrics in Poker Face are surprisingly strong for such a poppy record.