One decluttering technique that works well in the office environment is to reverse the process: start from scratch and add the items you actually need little by little. Take everything off your desk and out of your drawers, put them in a box and go back to work. When you need an item, put it back on the desk/in the drawer. If there are things you don't use after a few days, that's a pretty good indicator that you're holding on to it for no good reason…
Our brain tricks us into thinking that everything is important – the result? Clutter. When going through your stuff, ask yourself: does this item have a function? Is it superfluous or passé? Are you holding on to it because you need it, or because you may need it at some point in the near future/next decade/another dimension? Do you even remember how it got there? From the answers to those questions, you should have a good idea of what to do with it - even if you don't like the answer.
Now that you've correctly identified what is worth keeping, you need to next decide where to keep it. Where you put things is just as important, since quick access to the things you use most often is a priority. Organise your desk drawers by importance: the stuff you use most often goes in the closest drawer, while everything else goes in the storage spaces further away. If you use reams of paper, give your desk an L-to-R workflow: work comes in on the left, gets processed in the middle and goes out on the right.
Organising the mess of cables under (and on top of and to the left of and to the right of…) your desk is a never-ending skirmish, but you can take it to the next level with some simple tricks. Rain gutters make surprisingly great, cheap cable management tools. However, if all else fails, you could investigate the option to creatively display your cables when hiding them is not an option.
If you have too much important stuff that simply will not fit on your desk – no matter how hard you try - the next solution is to enlarge your workspace (or at least add some extra storage). To increase your storage space in a small room, think vertical: raise up your monitor and make use of the legroom under your desk. If you’re able to use every inch of space you have to your advantage in an organised fashion, you'll be better off than you were previously.
Everything that is used when sat at your desk should have a place it can call its own –where it lives when your workspace is spick and span. If items don't have a home, your desk becomes the squatting ground for everything. If struggling to stick to this principle, we advocate the loaf test: if it's smaller than a loaf of bread, hide it away in a drawer/shelf/storage pot.
No matter how organised you keep your workspace, it's going to get messy during the day. But that's okay – at least it means you're working! It's when you maintain the mess that things start to become a problem. To ensure this eventuality does not occur, clean off your desk every evening. By taking 5 or 10 minutes to straighten things up, you'll come into a clean desk every morning - ready to work (after the obligatory coffee/natter/social media peruse).