The deck is pretty straightforward. Get vampires, and beat the opponent down. In the process as an added bonus, you get a ton of life. You may be wondering why I have Oketra in here. It is because a 3/6 Double Strike is overpowered in this deck, especially because with all the tokens you are creating, plus the other creatures, she should almost always be able to attack and block. While life drain isn't a primary focus, it compliments the deck quite nicely, so I added that in.
Strategy wise, this deck is good because you want to be aggressive when playing it, but if things get dragged out, unlike other aggro decks, this one will not fall apart, or at least not fall apart fast. Ideally, you want to be launching a full scale assault as fast as possible, and with the life gain, the odds are you don't have to worry as much about taken damage. If you can kill them fast, that's great, but if you can't, I have seen this deck come back from three life, to winning with over thirty life. Despite being an aggressive deck, you still have to play smart and think about your decisions.
I am running all my exile cards in the sideboard, because I want the primary focus to center around creatures. Only in situations that call for exile, will we side those in. The basic lands are in there because as we change our sideboard, our amount of man of a certain color might change, and so this will help balance it. Our sideboard is made to only have to be used in certain situations, so we have a sideboard centered around a ton of different scenarios. Just pick which one fits best to the problem, and side it in for the ones that don't do well in the original match up.