Well, it really depends on the type of hacking.
Though they are related, TASing and ROM hacking are effectively branching down two different paths, though, they both can use similar resources to achieve a different result (A TASer wants to find out the statistics of a monster in an RPG to know how to work with them, a ROM hacker wants to know the same information in order to modify them).
In this case, you appear to want to know about ROM hacking specifically, it's probably a good idea that you would have made this topic in the
Off Topic discussion area (Though, I am actually a bit unsure myself... it's really a difficult question to sort into what forum and whatnot).
Anyway, this might not even be the best forum to ask the question, honestly.
Anyway, for what I can help with, I've found that editing bytes in the RAM to see if the layout changes could be a good start, I established how some of the layout is stored in Gourmet Paradise via this method
(TODO: Document how Gourmet Paradise stores its layout), though, this relies on a fair bit of luck and brute force in doing so... and even so, it relies on the layout being stored uncompressed inside the ROM. Talk to me on AIM, MSN or the TASVideos IRC channel if you want more information.
I admit I am probably not the best man for the task of answering this question, but I do welcome you to TASVideos.
Edit:
<Dacicus> Flurret: Send the newbie to romhacking.net
<Flurret> I never thought of that fff
I never visited there myself, but it's apparently useful.
