a. We all look like n00bs our first time in Second Life. Don't sweat it.
b. Not everyone wants to follow this step. There are regular Residents who have been around for years who still walk and type like newbies. That's their choice, that's their thing and glory hailballs for freedom of choice. Lots of other people, however, want to wash off that new avatar smell as soon as possible. Here's how.
1. Get out of the prefab Linden Lab skin you wore on day one. Change skin, shape and clothes.
2. Get an AO (animation overrider) and stop walking like you have a dried corncob up your ass.
3. Stop your typing animation.
4. Rez, do not wear, boxes. (This is one I still do to this day.)
5. Step off of landing points as soon as you can. (See the people hovering over you? They're waiting for you to get out of the way so they can land. More are coming. Move.)
6. Don't ask everyone you meet if you look sexy or if they wannafuck and don't tell every female avatar that you meet that they are really a guy.
7. Pay attention to region maturity levels and don't walk around naked or in XXX attire in General areas. And put your cock away.
8. Don't push people and don't walk or bump into them.
9. Check your screen for helpful IMs from the people around you.
10. Learn and practice some of the etiquette of the new culture you are in. Utilize some of the etiquette you learned in real life in Second Life too.
Links that may help:
Note: I keep linking RLetc.com. It's a third-party virtual world forum. You have to join and become a member to view the content. It's a small, quiet, easygoing little forum with good people in the membership ranks. It's a good place for new people to go and put their toes in the water without getting blasted by people who like to game forums. Also, back in 2010 I spent hours assembling a boatload of guides, many of which still contain a lot of useful and relevant information as well as links, slurls, screenshots and step-by-step instructions. Am I an expert in SL? Hell no. But as I went through those early days and figured stuff out, I made note and pic of it and I'm sharing it with you now. And only now. Use it or lose it.