The tips below can be found all over the internet, but I am happy to help get your suspension dialed in as well as walk you through what each adjustment does and typically where you will feel the changes. Every rider is different, and suspension allows you to tune the bike to your needs.
Step 1 - Set your Sag
I'll say it again, Set your Sag
Most manufactures recommend between 15–20% on the fork and 25–30% on the shock.
Notes: Sag controls everything that follows, so have a friend help and get it right!
Step 2 - Rebound
Most manufactures have a chart on the fork leg, or a service manual that tells you how many "Clicks" from "Closed" to set. These are starting points, but often very close. Don't discount them.
Notes: "Closed" rebound means the fork/shock will return to full extension at the slowest possible rate for that spring rate. "Open" means it will have the least amount of damping and return at full speed. Not enough rebound damping can cause a pogo effect and/or unweight the rider, causing a very unstable ride.
Step 3 - Compression
Compression is very rider preference, but there are some go-to's. In general, for forks, start in the middle of the settings and work from there. On shocks, it's often preferred to run more toward the open setting and work your way toward the closed as needed.
Notes: "Closed" rebound means the fork/shock will resist compression by restricting the oil flow to the max. "Open" means it will have the least amount of damping and be easy to compress.
Step 4 - Volume Spacers/Tokens
Most shocks and forks allow tuning of the bottom out, with volume spacers or tokens. Some even ship with them, which means you can pull them out for a more liner feel. I could go on and on about these tokens, but you'd stop reading.
Notes: Often people prevent bottom-out by adding air, but adding air changes the entire travel. Instead, use these tokens to ramp up the air volume and prevent bottom out, without impacting the initial part of the travel. They even make bottom-out stoppers for coil shocks, you could also use a progressive coil if you are blowing through travel.
Seriously though... I love doing suspension setup and watching the bikes come to life. I enjoy getting the baseline setup, then having the rider do a couple of runs and tell me what they like and what they don't. From there, we refine it until it's great.
Just don't tell me it's perfect, because there is always room for improvement and the suspension will change with riding conditions and even as you ride.