[{quoted}](name=Occams Raiser,realm=NA,application-id=3ErqAdtq,discussion-id=8HsAo5LR,comment-id=000a0000,timestamp=2016-01-27T15:28:52.273+0000)
that means you lost a weapon to poke with for the most part with the mana stacking.
On the other hand, he has better execute, better last-hitting minions with his R, because the 300% damage applies to them as well, as well as better chance of stealing Baron/Dragon because... it also works on them.
...unless the other team has Mundo. I don't think he counters anyone else.
My favorite matchups last ranked season were against Yasuo and Fizz - I didn't lose a game to them all season. With the rework, I don't have enough information to really go off of yet, but with an AP build, I don't expect it to change very much. I played a ranked game against Fizz yesterday, and my jungler fed him two kills early, but we still pulled out an easy win (played on my other account "AnotherMustache").
he needs to be tougher or do greater front loaded damage. Regardless of what first two items I pick, people stand with me going toe to toe, burst me down, and walk away with MORE than a sliver of health.
Then you are not poking them enough before they all-in you, or you are positioning poorly, or using your summoner spells poorly. Or you are sticking around with less health than you should. Remember that the faster you get your items, the better off you will be. So if you aren't getting your first two items until they have three items, of course they are going to kill you.
My starting items depend on my lane opponent, but I'm generally rushing Rod of Ages (Catalyst first) because it gives me a bunch of stuff that I want. Starting item depends on the matchup, but is typically Doran's Ring or the Dark Seal. I don't finish Mejai's right away, typically building Nashor's Tooth first, starting with Fiendish Codex.
It should be relatively easy to survive until level 6, especially against Bronze opponents. You can stay pretty safe, using your E to farm from range. Ideally, every time you hit a minion with your E, you will angle it so that it also hits your lane opponent. This isn't always with the goal of getting a kill... you want them to burn potions (which cost gold), or back for health (which costs them farm and experience), or to make them too scared to all-in you, because they might die. Trading kills with the midlaner generally works out better for Kog than the other guy, because Kog scales harder.
Also think about the order that your skills hit the opponent. If you are going to hit them with your Q and your E, which do you want to hit first? Assuming they are both going to hit, you would rather the Q lands first, because it reduces their MR and therefore makes your E hurt more. Plus if they are standing on your E, you'll be able to auto attack them more times with your W active.
Conserve your R. You never really could spam it for lane harass anyway. Use it to last hit minions, and pretty much always wait for the mana cost to reset in between uses. If it hits the enemy champ, fine, but if not, no big deal. But if they are very low, you better be trying to hit them with it. It will be easier to land the R if you hit them with your E first, because of the slow.
Things that Kog'maw's kit offers:
Armor and Magic resist shred, that benefits your whole team
Waveclear
Scouting brushes from range
AoE slow (works well with Liandry's)
Execute
DAMAGE
So let's say you are against an assassin Mid, who has low waveclear. Use your waveclear to your advantage. You can force them to stay in lane, or they lose tower. So either your team benefits from them not being able to roam, or they benefit from you taking tower. By the way, AP Kog, built correctly (which to me does not mean on-hit aside from Nashor's) takes towers very quickly.