Name: Hanmore Jemimah the Fourth
Location: the front line
I beg to differ with all these "don't EVER use broad matches" fools. Do you think Google are stupid or thieves or something? Do you think the option is there but should not be chosen at any stage at any point on any keywords? Actually broad matches are perfectly fine, it really depends on how many words you include in your phrase.
I'm not going to expand beyond that, but seriously, anyone new who is trying to understand google, you can see their own video tutorials easily (just google them) and ignore any silly idea that you should not use broad matches. You might well find that you want to bid on many many phrases which you set to broad match.
Also, in answer to the question, here's something I read which summed up just about all I had learned through experience with adwords. Two rules...
1. Don't overpay (overbid) for hits
2. Pause and delete ads/keywords/groups, don't just add them, ie keep on top of your ctr and if it's not good enough then kill off the ads which have bad ctr (if you fail to fix their ctr through other means, such as improving the ad text)
The first point is not likely to be emphasized on google's tutorials but I think that point 2 is fairly well covered, I mean it's quite obvious in the end - why would there BE ctr if it didn't matter to anyone.
The most painful pitfall to watch for is that your domain does not get given bad quality score - ie for getting too few clicks per 1000 exposures... you have to make sure you get the right people and give them the right message and that you KNOW you have done this by watching the numbers and staying on top of them and taking action quickly in any/all cases where they are failing.
Run only a few ads at a time - try not to let any ad have more than a few 100 exposures before you carry out the first pruning/adjusting.