They say it takes a village to raise a child, but when it comes to landing a new job, the same holds true. Chances are that at least a handful of people played a part (big or small) in creating this new opportunity for you, so make sure you don't forget to give credit where it's due and take some time to say thank you to anyone and everyone who was there along the way. This includes:
The hiring team at your new company, including your new manager, anyone you interviewed with, and any recruiters or coordinators who helped you through the process
Anyone who made introductions for you or helped you make a connection somewhere
Anyone who put their own reputation on the line by making a personal recommendation
Anyone who passed along your resume to someone with influence
Anyone who helped you with your resume or reread it after all 86 revisions...I feel like you at least owe them a drink or something, right?
Anyone who offered advice, assistance, an introduction, anything at all...even if they didn't help you with this particular job.
Friends and family who cheered you on, helped you pick out that new interview outfit, and kept you from giving up and bingeing on that tub of cookies & cream when you thought you'd never make it
I'm certain that I'm missing someone, but you get the idea, right? All this to say that your job search process isn't over once you sign the offer. Make sure you take the time to show some appreciation, even if it's just a simple, "thank you." It's proper human behavior, but it's also good karma and we can all use a little bit more of that, right?