Diversify globally. Be disciplined. Focus on long term. Have a written plan. Control what you can control. Be positive.Use index-like funds.
Today's @dominoproject related prompt was to write a message to yourself, 10 years from now, in the form of a text or tweet. A tweet is limited to 140 characters, as is the above advice.
This advice is short and concise, but I am very confident that 10 years from now, this will prove to be good advice, which will benefit those that adhere to it.