This is the build i have gained countless victories with. I want to point out that it is for a SOLO TOP Olaf and not a jungle set. Uploaded for a friend.

The reason i choose to level Undertow more is because solo laning as Olaf can be dangerous because of the melee. This will allow you to poke at your enemy(ies) and does quite a bit of damage early. It also helps push the lane out from the turret most of the time.

This rune set concentrates on giving early damage for being a solo laner, and also the bit of armor penetration that is required. Also attack speed because it is a filler but good for Olaf.

Built for the damage from offense with a bit of defense. The 4 defense points can obviously be moved around if there is something attainable but better for your playstyle. Other than that, everything in offense is taken that will benefit Olaf.

Ignite is always a good choice for dps melee champions, and flash (other than Olaf's ultimate) is his only means of escape. Exhaust can be taken instead of ignite to adhere to the players style.

This build is balancing damage and lifesteal to work well with Olaf's passive. The frozen mallet being one of the best items on him. Zeke's Herald, since the rework is an amazing item for him as well. The Youmuu's can be substituted for an Infinity Edge if desired. Also some players may want Wriggles lantern instead of Zeke's for the warding; being solo lane and all.

LAST HIT IS OBVIOUS. Other than that follow these helpful CS tips:

If your team has no jungler, I would highly recommend grabbing some jungle only under these circumstances adding to your loss of farm laning with a partner:

1. You need to base
2. You can sustain jungle damage and still return to lane healthy enough to hold
3. Your lane is pushed far enough giving you time to grab quick wraiths and wolves
4. return to lane after these
5. If you have more time, getting blue for mid is a great idea too XD

Some substitutions can be made in terms of items. If you prefer using W (Vicious Strikes) as your main damage output, you may want a warmogs/atmas type of build removing the Zeke's and Youmuu's for it.

This is the build I use for playing Olaf solo top. Even if i don't solo top, i still use this build because it is aimed more at damage and life steal to extend you sturdiness in team fights. It doesn't focus so much on the passive of Vicious Strikes, but more so on the overall damage and life steal with minor health items. It's a great build for harassing as solo or damaging as duo, but either way, you can AXE your way to victory!