Glad it went alright for you, and good luck with the next one!
(though seriously, get a TTL flash if you can)
I was just looking around for some good tutorials I remember from when I started with flashes, but my google fu is weak today, sorry!
TBH, If you know your exposure triangle and are confident in ambient light then it shouldn't take tooooo long to work out. Especially once you realise the relationship between f stops and flash power/distance (if you haven't already anyway).
You only need to remember the output power at a single ref distance, and then you can nail every shot first time.
ISL is our friend sometimes too!
Eg Say a flash on 1/4 power is gives you f11 at around 8ft away feet away. If you then need to take a pic from 5.6ft away you just click your flash power down a stop to 1/8 and fire away. If you then needed to move back (from 5.6ft) to 11ft away, you would slap the power up 2 stops to 1/2.
If your next shot then required you to bounce off a surface 8ft away, the distance to subject would be 16ft total. So from our original 1/4 power 8ft reference point, we just have to notch it up by 2 stops to 1/1 power to account for the double distance (or for example sake you could jiggle the aperture/iso around and rebalance the ambient shutter etc).
While at first you may wonder how to account for triangulation, its really a non-issue. As long as you measure/estimate distance from the flash > bounce point > subject, it all works out fine. You can get into some issues when more complex factors come in (such as flash zoom), but learning this technique will see you through most situations, or at least get you close enough with the first shot that a minor adjustment is all that's needed to bring it in line. Distances do not have to be exact either. All cameras fudge the numbers a bit , and so a few iffy estimates here and there make bugger all difference in the real world at typical event/portrait distances.
Other tips, try hanging around 1/2 x-sync for your shutter (so, usually 1/100 or so). This give you a stop more headroom in the ambient should it fluctuate later, and still allows you to drag the shutter down to 1/50 to let in a stop or more without risking blur at 50mm or so. If shooting wider angles you can open up the ambient quite a lot more for some slow sync shots if people are static. It's also fairly common to shoot at middle ISO's a lot for maximum flexibility (and less flash wear/battery drain). Pretty much all settings tend towards the middle as this affords the most amount of flexibility when composing for both the flash and the ambient factors on the fly.
Hopefully that'll give you something to play with for a bit anyway.
In the mean time... oh and did I mention that you should get a TTL flash?
