They introduced characters pretty well, but it needed more episodes to build on the foundation Help Wanted made, which was the plan ever since the show began being worked on.
From the episode, Spongebob is a sightly annoying, skill sea sponge who is kind of shy but very willing. The only thing that didn't pass on from this episode was his shyness, though traces of it were later shown. Patrick's lines about what Spongebob had been doing was basically saying he had always wanted to be a fry cook, and he was really a man wanting his dreams to come true.
Gary was barely introduce, mainly as a cat that Spongebob can understand. It wasn't until Plankton! and Naughty Nautical Neighbors did they slightly add to his characteristics. But like I said, it was always planned to have episodes that build on characters over time.
Patrick, on the other hand, was introduced as a half-witted sea star with some wisdom and natural comedy to his behavior. He helped push Spongebob towards his goals, and that was what he was there for (minus a funny gag at the end where he is shot out of the Krusty Krab).
Squidward was introduced as a citizen that is often the butt of the joke, and he doesn't like Spongebob, which is pretty much it. We are never shown what he likes or his characteristics, other than the fact that he is very grouchy all the time. Squidward is built up better in Reef Blower and Naughty Nautical Neghbors than in Help Wanted. Also, the citizens are barely ever seen to hate Squidward or make fun of him, with the exception of Squid Wood.
Mr Krabs's character underwent massive changes. He was a kind of knowing character, which of course stayed, but also in the episode he is considered a friend of Squidward, and a slightly mean character. He is shown taking advantage of Spongebob's childish behavior, but he also is turned by a huge amount of money, which introduced his greed factor.
The Bikini Bottomites; a stretch to be putting in this post, but really the anchovies can be considered citizens of Bikini Bottom. Therefore, the people of this small town are portrayed as savage, common senseless monsters. And they say "meep."
That concludes my proof I have no life, I guess.
