What made you feel you needed to adjust the mirrors straight away?
Maybe I'm lucky, but my 'scope tends to hold it's collimation well.
I don't think three hours on your first attempt is too bad though.
I spent a very wet and rainy afternoon getting to grips with collimation the first time I did it.
spillage's advice is spot on.
I've always used a cheshire and a collimation cap as in Astrobaby's guide, but having just watched the video above, it does seem a lot easier with a laser!
Saying that, it does get quicker and easier when you get the hang of it.
Stick in there, you will get it.