This is my first champion guide, but this champion have the highest performance and i would like to start helping people, that are new to Olaf.
You would first want to take the Blue buff for the duration on top for solo, If there is no jungle. Play aggressive but be safe don't charge in at low health don't risk your life for a possible kill, risk your life for a Certain kill.

The reason i chose to use the Greater Seal Of Alacrity for the attack speed increase when your health is lowered on Olaf your attack speed is buffed up even more. At low levels the armor penetration is a Game Changer so that's the reason i chose 6 Greater Marks Of Desolation, i also chose 3 Marks of strength for the damage upgrade. From what i have noticed, Olaf has a natural higher resistance to physical damage "armor", so i decided that he would need some magic resist to be able to sustain the damage of a top such as Diana, or fiddlesticks, even just the slightest magic damage done by anyone is gonna be reduced so that the reason i chose the Greater Glyph Of Warding. I also chose to use Greater Glyph Of Warding for the higher probability of being faced with the challenge of two people that both do physical damage.

I wont tell you a rotation that you can use to play Olaf because, Olaf is played conditionally all i can say is that i usually open with Vicious Strikes to start my damage at a higher pace, if you can get them on the run sooner the less damage you do to them, if i have them and it looks like they are committed to the fight use your Undertow and use it when ever it is available, try to lead them into your Undertow.

The specific mastery build i took the time and read and understood and learned how each point would go to use, for the basic run down on how the mastery's built him are a fast tank that jungles but yet still has the strength to chop his enemies up.

Ghost for the chase down, Ghost for the positioning, Ghost to get away, Exhaust to keep them there reduce there damage and get the kill.

As Olaf and Using this guide, chances are your gonna push them to they're turret and you can't fight if they are "turret hugging" so whats your next leveling option to let them push some but still level you up? The jungle run to the nearest monster and start to burn them down once you see the enemy closing in on your turret get back and push them back to they're turret.

Farm, Farm, Farm til about 25-30 minutes depending on how the game is going, Im not saying to completely ignore the team help out and jump in for the team fights but farming is what i consider the best thing to do for this time period, if you have the chance push the turret and end it but be careful you don't wanna get ganked and killed.