The most common signs of angels are synchronicities that most attribute to chance. You see 11:11 or rainbows extraordinarily often or a feather from a bird. These are apparent coincidences that signal the universe wants to alert you to something.
Finding a white feather.
Seeing flashes of light.
Associations you unconsciously make.
Seeing rainbows.
Tingling, goosebumps, or chills.
The feeling of being touched.
Seeing symbols and images in clouds.
Fragrances that give you a particular memory.