Get your smithing to 90 and get the Daedric Smithing perk. Get the necessary materials and smith it.
Or,
Get Conjuration to 90 and complete the Ritual Quest to get the Sigil Stone. Get the necessary materials and forge it at the Atronach Forge in the Midden.
For me, I wear the Guild Master's Armor set. For slaying dragons, I personally set aside an unenchanted improved Daedric Bow and Ebony Arrows. I wear the Ring of Peerless Archery and a necklace with 20% Fortify Archery enchantment.
The Daedric Bow gets to be Legendary and enchanted with Absorb Health once my Smithing and Enchanting are both maxed out.
Also, buy apparel like rings, golden necklaces, bracelets and so on. Then make enchantment potions and enchant your apparel with Fortify Smithing and wear that, it rates up your weapons damage. Also make strong Blacksmith potions and use them when you improve your Deadric swords with the grindstone.
If you don't have the Fortify Smithing enchantment, find a weapon that has that enchantment and Disenchant that weapon. It will delete the weapon in the proces, but know you can use the Fortify Smithing enchantment. Hope this isn't too catchy.
