In Islam the simple act of smiling to one another can be considered as charity. Including one with a good character, who is good and just with people, this too can be considered charity. 
The primary form of charity is donating money to the poor, to the construction of mosques, supporting widows and orphans. 

The Prophet (peace be upon him) said “Sadaqah extinguishes sin as water extinguishes fire” (Hadith, Tirmidhi). He also said that Allah offers relief on the Day of Judgement for those who give sadaqa: “The believer’s shade on the Day of Resurrection will be their charity” (Hadith, Tirmidhi).

Often the best charity is supporting those within your local area such as a neighbour or the local mosque. However sometimes it is difficult to seek those who need help, in which case donating to charities can be an easy and beneficial way of helping those in need.