Every good DBA/developer writes their code with some comments/instructions at the top. Now in many cases this is important to have visible when running the code as it may give advice on the results or what certain column values will mean. Now you can split the code window, like you can in Excel but to my mind that just decreases the amount of information on the screen as you are dividing it into more parts.
My preference is to collapse the section of code by clicking the 
at the top of the code section I want to execute and then highlight it with the mouse and run it, either with Ctrl + E or F5. This way we can read the comments about the script/results and see the results. Wonderful.
I hope this is of use to you, let me know your favourite SSMS tip or trick in the comments.