Will,
I've been brewing for a couple of years now. I started off doing the Kit & Kilo brews like you are (ie. using coopers cans and Brew enhancers etc.). I've since moved to Extract brewing, which I find I get a much better flavour of beer, as I can introduce additional flavours via steeping grains and hop additions etc.
All of my brews are in the fermenter for a total of 2 weeks, as I'm a weekend brewer and I've never had a problem. I generally dry-hop on Day 8 or 9 (for the last 7 to 5 days of the 14 day period). And I'll bottle on day 14 or 15.
If there is one thing I put a lot of effort into it would be sanitising everything that comes in contact with the brew. Can't emphasise this enough. Doing this poorly can kill all your time, effort and money.
Happy brewing!
Cheers,
Pete