playing new poppy so far, here are some tips for building

SKILL ORDER R>Q>E>W r is obvious, you want that ult q, again obvious, is your main damage ability, and will be used the most the thing i see people argue for is w vs e What people dont seem to understand is that W's passive doesn't upgrade with levels. all leveling it up does is 2 sec cooldown, 2% run speed, and 40 magic damage E level up is 1 sec cooldown (but on a much shorter cooldown to begin with), 20 damage (can proc twice if you hit wall) and 0.1 stun timer. Both sides are equally small, but the e being already on a shorter cooldown and the stun upgrade is more valuable than the run speed

now starting items. standard item, will work 95% of the time good vs harass lane, but the potion is better most times if you can guarantee that you wont need the safety of the pot/shield, get this.

these items are core no argument, always get these 2.

a lot of poppy's power is actually hidden in her passive, the single auto attack specifically. If you have the tf-sheen proc and a fully stacked deadman's, that's (at level 18) 124 base attack damage 190 from passive damage 100 from deadman's 25ad from tf stats 248 from tf proc that's 687 damage total, on the initial hit another 124 if you crit, because tf has crit chance so 801 damage on first hit if it crits. that's a ton, and to say your a tank and its ranged, that's incredibly powerful.

For boots, you can go any of these. if the enemy has 0 cc (or so little cc it doesn't matter) for a more offensive style. can also be used for a more utility style play if you find yourself constantly fighting in the jungle, or anywhere you can land lots of stuns use if the enemy has lots of ad (with the new ad changes that happens a lot but don't think it will stay for too much longer) your standard shoes. you know these, pretty much all tanks get them. You should play poppy as a semi-assassin fighter/tank. you rush in (not as the initiator, poppy has almost no initiation), throw everything at someone, and just duke it out after that. It may seem similar to Garen, but less aoe damage and more utility. The stat you want is hp. her passive shield is a 10% hp bonus essentially, so you want as much hp as you can get. the w is a armor/mr bonus too, but the passive refreshes, so you could at some level count it as healing. obviously a good combination of hp and resistances is best, but hp>armor+mr

extra items i see people use and my thoughts you don't have enough constant aoe to proc it enough. You're not Renekton, you don't hit all enemies 20 times in 10 seconds, you cant keep the stacks up. you can get more stats from better places decent if you want a more utility build, in combo with , but i prefer tf good all around item, and i would say its almost a standard item like i said deadman's/tf are, but doesn't provide enough imo. if your the initiator, do it. if your not, don't don't. just build tank, you'll be fine good item, especially with her passive, but only if you want to split-push, but i don't recommend that for poppy. see bork you can use this pretty well on her actually, since you can just stack hp on her. activate it before using passive and you can 2/3 a adc easy you wont be in the middle of all 5 enemies nor split-pushing, so don't do this. stats are nice, but there are better items pretty much core. lots of health and resistances. the stats you want mr version of randuiin's can be used both for the massive health and the passive. since you will be mostly sticking on one person, and poppy is semi-weak to kiting, this is good for her. if you need cdr, this is fine, but remember you want hp on poppy. if you want to get the risistances out of the way and just stack hp afterwards, get this, slot effecient for stats, and the passive is always good if they focus fire you. if you want to have fun, and are good with the passive, use this. don't rank with it, but its super fun to add that extra 200 damage, plus lots more crits.