1) I'm sorry for my written english, i don't use it so much, so i know i'm not writing very well.

2) I think that olaf is a really good and funny solotop champ cause his high burst early game and his high sustain.

For every 1% of his health missing, Olaf's attack speed increases by 1%.

This passive is good if you play in an aggressive way, cause it can helps you facing your enemy when the duel becoming hard.

Olaf throws an axe to a target location, dealing physical damage to units it passes through and slowing them for 2.5 seconds. If Olaf picks up the axe, the ability's cooldown is reduced by 4.5 seconds.

In my builds this skill is used for slowing scope only. Use it at the beginning for lowering the enemy life and after for reach him.

For 6 seconds, Olaf's attack damage is increased and he gains life steal and spell vamp.

This is grants you a lot of sustain, usefull for solotop gaming and allow you to survive to a 1vs1 or to a team fight. It gives you a nice bonus damage that scales well with this build.

Olaf attacks with such force that it deals true damage to his target.

Your main damage source. It does an insane damage early game and your enemy will be very scared by this skill ;)

(Passive): Olaf has increased armor penetration.
Armor Penetration: 10 / 20 / 30
(Active): Olaf instantly removes all crowd control effects from himself. He is also immune to disables (including silences and blinds) and gains bonus armor and magic resist.

This ulti is great for a malee fighter. It makes you immune to incoming disables and, after a recent patch, it removes all crown control too. The Armor/MR bonus helps you surviving in team fights and the ARP bonus will makes you hit harder. Really usefull in my opinion.

This way needs some skill to be played well and do not feed your enemy. In this way you will do TONS of damage with your Reckless Swing cause it does TONS of damage and you can burst your enemy if you attack him at the right moment. Anyway this playstyle is quite dangerous and you need to use your brain to do your job well. This is my favourite way cause it is very funny.
The strategy should be something like this: Undertow, Auto, take your axe and go back. repeat still enemy life go near to an half than kill his like a viking with Reckless Swing! use your Tough It Out to regenerate life hitting minions when you need it. Don't forget to activate it when you decide to kill your enemy.

Maybe a more boring way but you will be quite unkillable if you play defensive. Just throw your axe sometimes and hit with Reckless Swing when the enemy comes near you. For the rest of the time last hit minions and regen your life with Tough It Out. Done.

take this spell for the aggressive build. It will help you to kill your enemy doing damage and diminishing its health regen. No more missed kills for 20Hp ;)

this spell will help you to close distance if needed or to run away from a dangerous situation.

i love this spell when i'm playing solotop.. i think you will love it too.

Greater Mark of Attack Damage: give you early damage.. nice.

Greater Seal of Armor: early armor, you will need it early game.

Greater Glyph of Scaling Magic Resist: some MR mid and late game.. i think this rune is very nice.

greater quintessence of desolation: in my opinion a must have. in combination with Ragnarok you will ignore a lot of Armor and, early game you can do more damage to your enemy.

Wriggle's Lantern: you MUST HAVE this item cause it provide you armon, lifesteal, damage and first of all free wards. In my opinion it is the most important item for a solotop game and you should rush it asap.

Warmog's Armor: gives you a lot of health that will work fine with Tough It Out and it is good for your off tank role.

Atma's Impaler: combined with your defensive and healthy build this item will make you happy :D

These two items will give you all the defensive stats that you need with a nice active and a good movement speed bonus.

If the game is going well you should take TF and you will be a nightmare for your enemy team, if you need some more def so take FM.. Select one of these in base on how the game is going. TF will work very well with your Reckless Swing cause its short cd, granting you a lot of procs of the passive effect of this item.

I'm not a big fun of this item, but it quite obvious that is works very well with your Berserker Rage. In my opinion you should take it the enemy team has a lot of magic damage and/or a Karthus. Take it instead of Trinity Force or Frozen Mallet. You should take it when you are facing an AP enemy top, starting with an early Hexdrinker

Is olaf a good jungler? the answer is "yes", but i don't play him in this role because i like others champions more that him, like Hecarim, Skarner or Lee Sin. So i cannot help you for jungling issues.