Lamar Odom's battle with drugs, alcohol and depression almost cost him everything -- so he's telling Johnny Manziel the #1 thing he's gotta do to avoid the same traps.
"Put higher power first," Odom told TMZ Sports, "Whoever his God may be."
Lamar, of course, was in a coma for days after OD'ing at a brothel in Nevada ... but he continues to party hard despite his brush with death.
Johnny, meanwhile, says he's got his life back on track .