Wealth in Islam may be a blessing if it is used for purposes that are pleasing to Allah, and to help one obey Allah. It may be a calamity if it is used for evil purposes, or if it makes one proud and arrogant, or it distracts him from obeying and remembering Allah.

Some ways to maximize the reward of charity: 1- Give it in secret. 2- Give it when the need of the poor person is great. 3- When you hasten to give it at the time when wealth is abundant. 4- When the charity is given to a relative. 5- When you spend it when you are in need. 6- When it is done at times and in places that are of special virtue. 7- If it will have a good impact on the Muslims in general.

Sadaqah jariyah (ongoing charity) is a charity whose reward continues after a person dies. As for the charity of which the reward does not continue, that is not Sadaqah jariyah. For more, see the detailed answer.