Many of my clients are mid-career executives who have had no need to update their resume and/or LinkedIn profile in 10+ years and they don't even know where to begin.
If you haven't updated your resume in years, my biggest tip is to do a quick *brain dump* every day for the next 7 days to make sure that you capture all of the great results that you have delivered that aren't currently on your resume or in your LinkedIn profile.
This doesn't have to be anything structured - just take 5 or 10 minutes every day for a week to think about your key accomplishments (quantifying your results with numbers wherever you can). Don't forget about your volunteer or board contributions too - give yourself full credit for all of your efforts!
At the end of the week, you can get started on updating your resume and LinkedIn profile (and you'll feel better when you step back and see all of the great work that you have delivered).