I've recently started playing Rammus in ranked, and I'm noticing I get some very low creep scores. In my most recent match I managed a whopping 16! I did not find myself underleveled (Always about the same level as 1-2 of the enemy's players), but I was wondering if this is common when playing Rammus.

Here's an attachment of my most recent ranked Rammus matches to give you an idea of what I mean.

how do you build him? if you have to use your ult to farm because it has a low cd

Jungle creeps don't count in your score.

generally i dont find much trouble creeping with him in lane, hell end up with a lower cs than pretty much anyone else because he doesnt have any really decent farming ability until around level 6

If I see a large creep wave I like to roll into it and ulti if I have to clear it. If the minions are away I'll defensive ball curl. I try to get a sunfire quickly on Rammus just so he can farm better as well.

Here's a look at my two most recent Rammus games to give you guys an idea. Basically, I move to gank immediately after my first rotation, and I just almost never find my way back to farming a lane. At best I might get a second to kill the buffs or golems or what not but other than that I'm moving from lane to lane.

You can move from lane to lane pretty fast with powerball, then as others said, pop ult to clear a wave very fast (or DBC if minions are attacking you).

It's not so much a question of whether I can last hit with him. He has a pretty heavy early game auto attack so it's fairly easy. The issue is more, I feel like a pinball of sorts bouncing from lane to lane to attempt ganks, and even when they're successful, I have trouble keeping up in levels, always being at the lower end of the spectrum.

When you suceed in a gank, you should hang around and help push the lane if the opportunity presents itself. This lets you stick around and absorb some minion wave exp. You can be the guy that goes ahead of the tower to grab all the minions up, hit DBC, and recieve gold while your team mates knock the tower over.

Running around to gank lanes constantly is a great way to farm if you're sucessful a lot, but don't feel obligated to be on the move 100% of the time. If there is a lane not being farmed, consider going there yourself. Tremors has a short cooldown, and that + ball curl will make mincemeat of minion waves. Don't feel guilty about snacking on a wave or two here and there if you have the mana to spare for it.

If I start lingering in lanes to farm between ganks, how many creep kills should I expect to be able nab in an average game?