As My Name Suggests, I Am The King Of The Nether, Always Finding A Way To Make A perfect Spawn/ Portal Placement.
My Tactic Is have Your portal Face North, As this Works For Some odd Reason.. No Trees, Just a flat plain.Make Sure it is about 10 blocks underground...
This Has Always Been My Tactic, And It Has Never Failed Me. Just Remember To Go In With Iron Or Better Armor. And Make Sure You Have About 5 Stacks Of cobble to Make A Defense. And Maybe a Couple Of Stacks of Arrows And A Bow.. That Always Seems to Help. Other Then that... Enjoy..