What should I expect, and what advice do you have, regarding my transition from LCpl to Cpl?

I’ve noticed that all ready. Most of my friends that are still lances aren’t taking me very seriously, which is a problem I’m currently looking to correct.

That's often difficult which is why when possible, a promotion usually comes along with a lateral transfer to another section/platoon/company/etc. However, I've been in many units where people get promoted and stay in the same group just due to the make up of the type of unit. It will not be easy but as long as you carry your rank seriously, you're all still Marines and they should take your directives because it is usually being passed down from someone above you. Maintain your military bearing, and they as Lcpls should come to respect you for your rank you earned, just as they will want the same respect when they get promoted. When I was promoted after showing up to one of my units, I didn't associate as much with the other E4s as I knew it was only a matter of time before I had my E5 so it was a little easier, but even as an E4, I carried myself as a professional. I socialize with my soldiers, and usually couch my directives to them from above as requests, but they know if I seriously have to phrase it as more than a polite request, they've crossed my thresh hold of politeness and know it will be a rephrasing as "do it now, or you can expect to beat your face or a counseling next". If you now are in a supervisory capacity to your Lcpl friends, step one being an initial counseling of expectations is a good time to have the conversation about respect and military discipline. Someone will always be promoted faster than someone else.

I appreciate it MSgt, all this advice is more than I anticipated and while it’s going to be hard to cut some of these ties I know it’s going to be required and expected of me.

I’ve had some good mentors in the past, most of which has EASd or PCSd since but I appreciate the advice, thank you Sgt.