The Main Stratergy of the deck is the basic Dark Magician stratergy. Eternal Soul and Circle are the bread and butter of the deck. this deck is mainly based on being a pure build with as little help from other stratergies as possible. (I find them more fun that way) I use Ash Blossom personally because of how generic it is as a negate and hits most decks. Yes as the norm for DM Decks at the moment, Verte Anaconda, Red-Eyes fusion and Dragoon are here, however it is not the main stratergy of my deck. I use the Spellbook draw engine over cards like Allure Of Darkness because of the downside of Allure aswell as the Spellbook Engine deck thins allowing me to get to the key combo pieces quickly.
Dark Magician Girl is a marmite subject among DM players, However in my opinion the upsides of being able to utilize The Dark Magicians floating effect and a extra draw off of Soul Servant is too good to ignore in my personal opinion. Bond and Dark Burning magic have been a tech in my tech since their release, apart from Burning Magic being my favorite card, it has won me games more times then i can count purely because nobody expects it. However, ido understand why people choose not to run it.
As for tech cards and side deck its up to you what cards you want to run. Dark Magic Veil is a good card for this deck, allowing you to summon from your hand or from the GY to summon up those powerful Dark Spellcasters. I like Secret Village as it always works well with a spellcaster deck. The solemns cards are brilliant. I find myself going between Solemn Strike and Solemn Judgement but at the moment i find myself wanting solemn strikes. The virus cards are also very well suited to a DM deck. One of My personal favorite techs is Dark Renewel, basically acting as a Solemn Strike and riding the feild of your opponents monster but giving you a summon from the GY or Deck at the same time.