Most cable guides start behind the desk. That is the wrong end. The cables you can see from where you sit are perhaps three; the ones behind the desk are ten and nobody looks at them.
Do it in this order
1. Unplug everything and count
Not metaphorically — actually unplug. You will find two or three cables going to devices you no longer own. That is the cheapest win available and it costs nothing.
2. Decide which cables must move and which never move
A monitor cable never moves. A phone cable moves every day. These need different treatment: the first can be bundled permanently, the second needs to stay reachable. Bundling a cable you use daily is how you end up undoing the bundle within a week.
3. Fix the crossing cables first
Any cable that crosses the open desk surface is doing most of the visual damage. Route it along the back edge or under the lip. One cable moved off the surface changes the look more than five cables tidied behind.
4. Then the drop
The vertical run from desk to floor is the second most visible. Gather it into a single column rather than a fan. A sleeve or a few straps are enough; a tray is only worth it if you also have a power strip to lift.
5. Leave slack at both ends
The most common mistake is pulling everything tight. A cable under tension puts strain on the port, and the first time you move the monitor you undo the whole job. Leave a loop at each end.
What not to bother with
Hiding every cable behind the desk is a lot of work for something nobody sees. Adhesive clips on a dusty or textured surface will fall off — clean the surface first with alcohol and let it dry, or use a clamp instead. And do not run power and audio cables bundled tightly together over long distances if you hear interference; separating them a few centimetres usually fixes it.