When others compliment you on a speech, presentation, or contribution obviously say “thank you” but also follow up with “What did you like especially?” You will find a host of content that you said (and didn’t say!) in their answer.
Ask your boss why they hired you. Ask your customers why they buy from you. Ask your spouse why they stay with you. Ask your children their favorite memory of the two of you. And finally look soulfully into your dog’s eyes and ask why he loves you! (Be careful attempting this with cats!) Ask and you shall find an abundance of what makes you valuable, no need to guess.