All im going to say - is take on more then 1 enemy survive and kill them both - need i say more? i clocked up almost 5.5khp with this build - enough mana to do what ever i need and if ur running low - go get blue - but ur clarity will keep a prolonged fight. your passive will proc more with more enemies/ allies around so passive healing will proc quickly - you have UBER amount of regen as well and dmg reduction from your ULT - havent seen much use to this apart from mitigation its activation doesnt really do much dmg but good for popping a bit more off them as they run away.

A lovely amount of resi and arm here as well - enough to keep anyone who hasnt got and penetration SCREWED against you.

I buy 2 regrowth pendants first then ninja tabi full. Giants belt and ruby crystal and saphire crystal. Next comes my first warmog, then another giant belt. My second warmog is the next thing. then build the catalyst and buy more regrowth pendants. Complete the rod of ages and the the force of nature, leaving you finally with frozen heart - but u prob wont have all the money so build the glacial shroud section until u can upgrade it.

Use your twisted advance to either make a push with ur lane partner or to chase down someone they are nuking dont let them escape by using ur ignite when ur at max safe range from tower/ partner etc. dont be affraid to let them go if you CANT kill them better to survive and regen then to push and die urself - i made that mistake a few times at start.

Ur sapling is a good way to niggle away at their hp now and finish them off with an advance with ur team mate - co-ordination maybe necessary with a good opposition. This is how you want to play until u get your first warmog.

Now u can be quite aggressive due to ur majorly increased survivability through hp, regen and passive proc's - buy some mana pots if its causing u an issue through long spats. u will start to notice that you are becoming quite tough quickly. upon ur second warmog - unless a rush goes completely awry use ure ult to engage an enemy - giving dmg mitigation - and rush in with advance so that if they try to run it should be off cd by then and u can give chase. as soon as you have your force/ rod - u can mix it up a bit if you like but i pref the extra mana and slight AP increase first you will be pretty uber tank like. when u have your 5 items - there not much they can do to you now - be carefull of lockdowns but if your with your team mates you can cause a lot of annoyance while they rip into them. your last item will protect you against the AD haste chars - and you should be VERY comfortable going up against anyone of the enemy and winning - i went up agaisnt 4 of them and they all died thinking they could rip into my 'juggernaught' build but failed miserably - oh and i was on my own,

So just to summerise your build - 5.5k hp, hp regen, ur passive proc heals in group fights fires off rapidly, your ult preventing 20% dmg and ur arm + resi providing u the additional bark skin u need and the passive from heart slowing those pesky haste chaps - you could possibly get randuins here but i like the additional mana, Ryali is also a nice 1 for the ability slow annd even more HP + top up to AP but would be very situational.

My mastery is as much mitigation as possible + resi from my runes so u dont have to worry about sacrificing hp/ regen for that.

With pretty colours and a baby tree to fling around what more could u want lol