How to earn thousand good deeds ?

Sa'd bin Abu Waqqas (May Allah be pleased with him) reported:
We were with the Messenger of Allah (pbuh) when he asked, "Is anyone of you unable to earn a thousand good deeds?" One of those present asked: "How can one earn thousand good deeds in a day?" He (pbuh) replied, "By saying: Subhan Allah a hundred times, then one thousand good deeds will be recorded for him or one thousand sins will be blotted out from his record."

[Muslim]