The phrases listed in this bereavement article should be avoided when composing a condolence letter.
Almost every sentiment found in a greeting card, clichéd or not, is well-intentioned. That said, many phrases that are widely used can still come across as incredibly insensitive, if not downright offensive. Make sure that your words of comfort and sympathy are supportive, not inadvertently harmful.
Avoid the following phrases, or at least use them with caution:
"This too shall pass."
"It gets better/easier."
"Try to keep busy."
"I know exactly how you feel."
"She's in a better place."
"This is part of God's plan for him."
"She lived a long, full life."
"At least he's no longer in pain."
"At least she didn't suffer."
"It was his time to go."
"This might be a blessing in disguise."
"Take comfort in God."