Questions

“”The best way to say sorry is not to say sorry at all, unless you have done something intentional and you felt wrong and guilty about it. See, people your apologize are precious to you. Your value is affected by saying sorry or apologizing to people. So unless you do something wrong INTENSIONALLY and feel bad about it do not say sorry. Make your apology creditable..

Now what do I say instead of saying sorry? Or what do I do to make it up to someone who you have disappointed?

See, first of all you are not the one who disappointed them, it's just that they expected something out of you and they got disappointed..
It isn't wrong to expect something out of someone either.
SO THIS IS WHAT YOU DO.
Rather than saying "SORRY", say "THANK YOU". Appreciate them for what they have done for you. Understood?
Say, you are late to meet someone for about an hour, and they waited for you for an hour. Don't go and say "I am so sorry for being late, sorry but there was traffic." Say "oh I am so late, thank you for being so patient and for waiting for me, traffic was terrible today."
Another
Say, you have disappointed some one, say you fail to do something. You don't go and say "Sorry, I couldn't do it, sorry for disappointing you, I hope to do better next time." The other person won't appreciate your apologize. But, if you say something like. "Thanks for keeping your hope on me all this time, I know I couldn't do what you wanted but next time I will try my best."
Guy try it it's like magic.
The power of a thankyou is amazing.

Remember
Don't say sorry, say thank you. “”