I've recently returned to the game after about a five month break and picked up with my lvl 50 BLM again. I've perused the forums a bit to determine what stats/gear to focus on buuuut- ALL the posts seem to deal with gear. I think I have a decent handle on how to gear my BLM based on my budget, but one thing is still missing- I can't seem to find a guide on how to properly play the job.

I don't currently have a linkshell to ask around in so I have no idea about which skills are the most useful to grab from PUG and ARC, when is the best time to use excruciate, when should I cast Thundaga vs. just casting thunder -> thundara. I see bits and pieces about these topics- mostly they deal with people insulting the "urdoinitwrong" BLM's for missing all the bonus damage from proper spell progressions/cooldown usage. Well, I don't want to be one of those mages!!

Does a decent (recent) guide exist? If not, can anyone give me a brief synopsis?

My current "relevant" stats (mostly GC stuff- no $$ for materia) [with sanction but w/o food or buffs] are:
macc- 464
int- 344 (a bit low, I know- using Flame Sergeant's Cudgel until I can afford materia for Lightning Brand)
amp- 500
underleveled subs: PUG- 15, ARC- 1

Any indicator of the best cross class abilities would be great!