How do you build him?
IMO you should max poof first. At level 4 with 5 Meepos that ability means 1400 magic damage with a smallish AoE. So OP. This is where his damage comes from early game, not so much from his right-clicks.
Get a bassy ring early then get get treads (tranquils if you're a woos

). Then if your lane is going well go straight for that aghs, if going bad maybe try for at least some lifesteal or the headdress with the goal of reaching vlads. After aghs and vlads go for either a blink if you're finding you're surviving OK or go straight for heart (reaver first). Stack hearts (the regen doesn't go to the other Meepos but the stats do, Skadi can also be a good idea, some Meepos even go for a hex) and definitely late game get BoTs because each Meepo gets an independent cooldown on the boots.
Also if you see a DD rune as a Meepo pick that schit up and make sure all the Meepos are there when you do. DD applies to all the Meepos within a 500 AoE so your whole squad of Meepos can get DD at once from 1 rune.
When you get multiple meepos up just make sure to keep them all busy all the time and you farm fast. You can hit 3 or 4 jungle camps simultaneously with him. Or 3 camps and keep 1 in lane. Crazy farm. 2 level 4 poofs pretty much clears most jungle camps.
Also don't meepo against a lich... just don't do it!!!