Tip: Layer 3 backgrounds and tides disappear when you hit a message box, so plan your level around that. For example, you can add a sublevel without layer 3 at the start/midpoint, and include your message there.
Over the course of the past few years, in order to help others with learning ASM, I've continuously worked on and released my ASM tutorial. I now have two ASM tutorials, one focused on opcodes and one which gets you started with ASM hacking. Feel free to check them out!
If you want to edit my submissions, you have my permission. In fact, you can even submit them back to the Central. It'll simply mean more (improved) resources for the hackers out there which is a good thing. Please, just make sure you credit me in your version of the resource (and your hack if you end up using them).
Random stuffI used to collect screenshots for over a year. These screenshots show what you should NOT do while hacking SMW. You can find the screenshots here: http://s325.photobucket.com/albums/k364/Ersan00b/
Please make sure you keep your sanity while browsing these.