Tax-efficient giving

Bullet points: 
How much money might you be able to give, and over what time period?
Is this likely to be a lump sum (for example, from the sale of a company, a block of shares or an inheritance)?
Would you like to give non-cash assets (such as shares or property)?
Does your company have a payroll giving scheme so that you can give out of gross earnings?
Would you like to leave money to charities in your will?
Would you like to make sure that your donations continue after your death?
Are there time-sensitive tax considerations (such as giving shares to a charity to obtain tax relief on the gift in the current tax year) that influence your decision?
Would you like to make cross-border gifts?