Thanks for all of the input. I will research them all.

Thanks for the info. I never thought about the master unit issues.

I have a Canon T2i and a Sigma EF-610 DG ST flash unit.
Although I am hardly proficient with the ins and outs of flash photography, I want a Speedlite 430 ex II (which I probably should have purchased in the first place). Is this a good decision for a novice flash user or should I continue with my current flash?

Thanks for the advice. I refuse to give up by going back to auto mode. I will try the above suggestions. I do recall the shutter not operating at a fast speed.

I have a Canon T2i and am trying to move out of the auto mode. I have been experimenting with aperture settings, but a lot of my shots are blurred. I have changed the aperture settings and the ISO settings, but can't seem to find the right combination. Is there a "general" rule of thumb for these settings when taking shots indoor and outdoor?