Morde is my absolute favorite champion, I've played him to the point where I believe I've mastered this old bruiser. Morde is an ap bruiser or as we somtimes take him an ad bruiser, that can also double as a tank. Morde provides massive damage, fantastic sustain when played right, and a lot of fun. Coupled with a unique skill set and high skill high reward game play Morde can make for a great top lane carry.

While this guide is not yet done I have (obviously) already posted it so bear with me and wait for updates. Furthermore, after some more practice in the field of jungling with Morde, I might add a section for that here.

Pro's:
Strong Sustain
Massive Damage
Strong Objective Focus
Great When Mastered
Versatile
Snowballer
Con's:
Kited easily
Can fall behind
Hard to master (not as hard as most champs though)
Awkward Item Build

Some explanation?
Morde's passive provides a strong shield and his W can keeps his health high despite low starting regen, and health costs on his abilities.
Morde has strong objective focus in his kit as he can farm quickly with his kit, has a strong tower destroyer with his Q, and is great for getting drag or even another player to help out in a push with his ultimate.
Morde is versatile in the sense that he is a jack of all trades and a master of none. This makes him awkward as he can be played in many roles, with different item builds, but also makes him very weak in the sense that he dosen't overly excel at much.
On the topic or Snowballing or Falling Behind; Morde's entire game can be decided in his laning phase. Morde will rather when lane and gain a large advantage or lose lane and become nearly useless until late game.
Morde lacks mobility and can be kited easily by mobile assassins or adcs. That's why we build proto-belt or movement speed when we can!

For start you will always run 1 pot and a Doran's Shield, no exceptions!

As for the Early game: Corrupting potion when you are behind coupled with some tanky items like sunfire cape will allow you to come back and continue to farm without feeding.
When you are winning take your advantage by the tail and tug on it for as long as possible, what I mean is rush a dps item that allows for snowballing (proto-belt is a great example).

Later in the game anything tanky or that benefits you mobility problem (slows, movement speed, etc.) along with an occasional damage item helps a lot.

AD Reasoning: At first it was a joke based on old ADC morde, but because it worked I tried it again. It's great when there is a lack of AD on your team or if your enemy laner already starts building MR, in which case you can waste all that gold they just spent by going AD. With black cleaver in such a good place I naturally go it first, coupled with titanic hydra later for more damage and more farm makes the build pretty solid. As for later in the game I typically go Tank, but I will explore some more ad items and see if maybe full AD morde will work (I'll post updates here when I discover something new). So that's my reasoning for AD morde, try it yourself once you can play AP or Tank (tank being what I think is the easiest) morde well.

Last note: avoid gunblade as proto-belt is better and gargoyle's stoneplate as it subtracts your damage output.