Glad you're enjoying the mud! Especially since you have experience with other muds as well, make sure you post your thoughts and suggestions on the forums for us. Discussion is always good.

Now, regarding shrines. Asking IC is exactly the way to do it. The most preferable would be finding a tattooed and/or titled follower of the god you wish to follow, and asking them for help. Some will take you there themselves, some will give you hints, and others might not help you at all... obviously it is going to vary from character to character. Just ask completely IC and roleplay it out. Some gods followers don't have titles, or they may not have anyone with their tattoo currently. In that case, try asking other appropriate people. Looking for Shokai's shrine? Find a paladin hero and ask them. Looking for Khasotholas? Try bribing an Imperial. I personally have been known to give hints to my followers if you let me know via notes and prayers that you are looking for my shrine but can't find it. That's up to the individual immortal though. Also, many immortal helpfiles have a hint in them.

As for cabals vs. guilds. Cabals are going to be the same thing as the "clans" you've experienced elsewhere, I believe. The cabal helpfile should be fairly clear. Guilds tend to refer to your profession... thief, warrior, etc. Most guilds have very little structure within, though the paladins guild will have a lot more then the warriors guild. The exception is thieves, who have a very intricate guild system, with different guildmasters teaching different thief professions. Some thieves join cabals, some thieves just work within their thieves guild... many do both to one degree or another.

Good luck!
Velk