If, in a given year, you’re both going to:
1) donate to charity, and
2) sell stocks (or ether, or bitcoins, etc.) that have gone up in value
You should donate the stocks (or ether or bitcoins) directly to the charity, rather than selling and donating the proceeds. This way the charity ends up with more money and you pay less in income taxes.
Suppose you bought $1000 worth of ether, and it’s now worth $2000. Consider two possibilities, 1) you sell the ether and then donate the proceeds, or 2) you donate the ether directly to a charity that’s set up to accept them.
1) Sell and then donate. You pay 15% on long-term capital gains tax (see the edit below for assets held less than a year), leaving $1850 left to donate.
You can take an income tax deduction on this $1850, saving you ~$550 on your income taxes (depending on bracket).
So the charity gets $1850, and you save ~$550 on income taxes.
2) Donate directly. The charity sells the ether for $2000 (and pays no capital gains tax, because they’re a 501©(3) or whatever).
You can take an income tax deduction on the full $2000, saving you ~$600 on your income taxes (depending on bracket).
So in this scenario the charity gets $2000, and you save ~$600 on income taxes.
EDIT: The above only applies to assets that have been held at least a year (which would be taxed at the long-term capital gains rate). For assets that would be taxed at the short-term capital gains rate, you can only deduct what you paid for them (your cost basis) when you donate them. (See: http://www.gordonfischerlawfirm.com/gifts-of-long-term-versus-short-term-capital-gain-property/) Thanks to Alexander Rapp for pointing this out to me.