Im pretty sure this is common knowledge but here we go
1.Look Up You Video Card On The Internet and see if its a good one.
MapleStory requires rudamentary 3D interaction, the video card won't really matter.
2.Try deleting unnecessary items.
I think you mean, "try de-activating non-essential processes in Task Manager (uses Google to look them up)." Because that'll make more sense.
3.Get @ least a 1GB memory upgrade
That's a stupid suggestion, it just depends how much RAM memory you have. While MapleStory does have alot of data files, it's not uncommon for the programs to be built with a more advanced system so it doesn't just load all of them hogging your RAM. A mere sugggestion would be is to make sure you have enough free RAM space.
4. Check the Server You In. I notved the servers with more peple lag less then servers with less people.
That makes no sense, the servers will only be as fast as the internet connection, Nexon only uses dedicated server groups which can handle way more information. The only lag you are experiencing is your own, and has nothing to do with the amount of people in each server.