We started this community with the goal of making it the best place to learn competitive programming. Hint by hint solutions play a big role in that.

As more and more people start writing hints, I thought it would be helpful if I penned down some of my thoughts on writing high quality hints.

1. The most important thing is the difference between a solution vs the dissection process. A dissection process captures your thoughts, and how you broke down the problem. Don't just say, "use heaps". Say the observation about the data, and hence heaps is a good data structure to use. Don't say, "use dynamic programming". Say why first.
2. Spend time figuring out if your solution is the simplest possible. When solving a problem, we come up with observations that we don't end up using in the solution. Writing (and worse, coding!) that makes things confusing for everyone (and you, while debugging!).
3. Use small examples. Algebra is tougher to read and write, and its easy to make typos. Also, you usually use examples to solve the problem. Write those down.
4. When I find it difficult to write a particular hint, its often because I'm trying to cram too many things in one hint. Again, thats tough to write and tough to read. One step at a time works best.
5. Remember who you are writing for. If its a really tough problem with 3 sub-problems, then you're not writing for beginners. So its okay to skip explaining the details of how to solve the sub-problems.

More tips coming soon... I'll keep updating this list as I read more hints and see patterns of similar mistakes.