You're new in the writing business. Or not new so much as being, worse yet, unknown. You decide to self publish and go via the epub route. Bigger audience. Better potential in keeping your work out on the market for longer periods of time. Maybe eventually a bigger payday all away around.
You've read all the accounts of how other writers have done this and the successes they've had. Not forgetting they are/were a known product . . . and you're an unknown product . . . the decision has been made. Screw tradtional publishing. On to that bright, undiscovered country!
And then stark reality slaps you in the face. How do you become known? Why would anyone want to buy your works over, say, ten million other scribes? What do you do to separate you from the growing crowd of other struggling writers?
Got any ideas?
The intimidating part is what I charge to do all that. :-D
In seriousness, even doing just a couple of those points is better than nothing, and might even help a little bit.
Of course, in an ideal world, your publisher would do all this, and more...but alas we don't publish in an idea world.
What not to do: probably best to resist gimmicks and watch out for that buzz-phrase 'add value' - I've seen pop groups 'adding value' by becoming waiters and chefs at their own gigs, by selling personal possessions, by giving away their music for free in the hope that someone will buy a T shirt instead. The music becomes irrelevant.
What to do (beyond writing something wonderful): most of what Clay says or hire a PR company. (Although, it's got to be said, what Clay suggests isn't hard, just time consuming).