I think writing needs to be a writer's top priority when it comes to their books - not marketing... that's gotta be the golden rule. Easier said than done, though, I guess
I can't claim to be an expert at this stuff, by any means. When it comes to marketing, I've tried to make use of methods which will have a flow-on effect for the times when I just couldn't be bothered. The first marketing I did for DEAD(ish) - and probably the most effective - was to start my @onlinefiction twitter account and market the hell out of a lot of people's free fiction, not just my own (note to the curious - this has been put on hold not because I'm done with marketing atm, but because I've been without home internet for months). That garnered me a surprising amount of goodwill, and I think I've been coasting on that for the last few months
The other two big (in terms of results) marketing choices were to join this forum and the
NookBoards and just get involved in the community. But posting on a forum like this is leisure-time for me, not work, so I can kill two birds with one stone
I'll admit I've been just plain lucky in the amount of publicity DEAD(ish) has received, though. I've been able to just sit back and let word of mouth spread... a lot of people have written reviews, passed it onto friends, retweeted info about it. I think people's willingness to try it out is partly due to the length (not a huge time investment) and partly due to the cover that MoeJoe designed for me.