When you have relationships with people, you will want to show them how much they mean to you especially when you have pulled through rough times. There are many ways where you can say thank you for everything you've done for me. If you want to really show someone that you care, you can write them a letter. Yes, we live in a digital world, but a handwritten letter still touches people's heart. It is the gesture that counts, and you want to show them that they are worth your time.
Also, just saying the words to someone means a lot. More often than not, we go through this world holding back and not saying things that we should. You can stop this today by calling each person that you care about in your life, and telling them just how much they mean to you. Nobody is guaranteed a tomorrow, so it is important that you tell them how you feel before it is too late.