My brother asked me to run a one-shot for him and his friends on his birthday yesterday, and I did. They all had a lot of fun and asked if I could run a weekly campaign for them. I agreed, but I'm starting to get worried that my brother might take over the campaign. In the one-shot he did a good job of not making it all about him, but he was very much a leader of the group and made a lot of the decisions. Any advice on making sure that this is going to be an equal campaign?

It may be helpful to tailor some adventures to the skills and backstory of some of the other PCs.  Newbies don't always realize what their skills do, or have detailed backstory.  It might help them if you have a conversation with the group (maybe your brother starts) where everyone talks about what matters to their characters and where they come from.  I'm about to play with a group where only one person has experience, so one way I'm going to try to get this kind of conversation going is to have everyone roll on the trinkets table, and then brainstorm (together) why their character holds onto this item.  Sometimes, new players just need to have their imaginations primed.

I would say that you need to keep an eye on it, and make sure he doesn't steal people's thunder. But, it is super helpful to have an experienced player among new ones, to help them out. Also, they will learn from him and get more comfortable over time. Make an effort to include them and make sure they are all participating, but don't worry about it *too* much. Usually what happens is, after a few sessions the new players get their "sea legs" and start to do just fine.

Address this now before it gets worse. Talk to your brother. Tell him your concerns and maybe watch some Critical Role with him so he can see how groups share the spotlight. 

As DM there’s nothing I enjoy more than watching the players role play with each other. If one player is spotlight hogging, that hurts my fun as well as everyone else’s. 

Also, as DM you can say “Hey, that’s great but we do need to hear from the rest of the table.” Then address the character sitting next to them or have the npc address another character besides him. 

Quote from A_Literal_Lesbian >>

My brother asked me to run a one-shot for him and his friends on his birthday yesterday, and I did. They all had a lot of fun and asked if I could run a weekly campaign for them. I agreed, but I'm starting to get worried that my brother might take over the campaign. In the one-shot he did a good job of not making it all about him, but he was very much a leader of the group and made a lot of the decisions. Any advice on making sure that this is going to be an equal campaign?

Best suggestion I can make is talk to your brother. Explain your concerns and see if the two of you can work together to help the new players both become more comfortable with the game and build the confidence to try and take charge or speak up on what their character thinks or wants.

I've seen this sort of thing a lot where inexperienced players tend to look toward the more experienced player to make the decisions for the party. It takes time but the newer folks will get over that instinct eventually; it tends to come with experience.

Definitely if the single experienced player can encourage the new players by asking for their advice, or asking them questions about the situation (even when the experienced player knows the answer) - sometimes asking leading questions can get the new players more engaged and thinking about the various problems they encounter.

Little late to the show, but I was part of a group of inexperienced players, while I had played a fair bit (albeit looong ago)  In that campaign, I chose a Bard, to make sure we had a lot of versatility, and as a Charisma based character, "led" the group, being the voice most times and making many of the decisions (although I did try to encourage discussion, to find the "best" solution)  It's situational, and if he was leading the party, but seeking input and pushing the others at times to be involved, it may have been a coaching by example.  

In the second campaign we've run, I chose a Monk who is rather socially awkward and creates some friction if he has to speak to NPC's most times.  Watching my companions stumble through some encounters (and knowing a a few different tactics we could use to make it much easier) is a combination of fun and irritating, again, depending on details.  We are moving along and a few times, they have mentioned our earlier campaign seemed a lot smoother.  I grin and we agree, learning and sometimes doing things awkwardly is part of the fun, so we carry on.  (Also, my Monk has breezed us through a few puzzles, as solving things is one of his strengths)

If it needs addressing, I would suggest letting him know that playing the sidekick, or muscle in the group is as much or more fun, when the player (but not the character) knows stuff that could help the group, but can't share. There have been a handful of times already, where our DM grins in my direction, knowing I would know how best to handle a social situation, but my character would be clueless.  If called on, I try to offer helpful tips, but if my character is pushed into speaking for us, it often results in someone (NPC) being offended.