Become very active yourself.  Comment often.  Answer questions often.  Write compelling posts and establish relationships within the community.

Pay it forward first. When I first joined AR there were only about 20,000 members or even less, can't remember for sure. It was way back in 2007. I made it a point when I joined to make sure I add value.. help others... and pay it forward. In fact, my very first post I wrote on AR states my goal and purpose for being here. 

So back then, we had not university, no webinars, heck.. we were all just learning how to add an image into a blog post! We had not Q & A, we had no guides or ambassadors, etc. 

I reached out by calling members, meeting with members, always commenting on at least 50 posts per day... writing content that would help agents, and always replying to comments. 

Groups were also much more active back then. It is tough since Facebook became so mainstream to be involved in groups here. The FB groups are so valuable and focused, ( the ones I am joined are). 

But for good groups here on AR; Bananatude is the best. 

Hope that helps. 

By far, the best way is comment on other people's blog posts (and I suppose follow them, so you see their posts, and some may follow back).

You must engage with others..comment on others posts. Answer questions like Susan Emo comments and Michael J. Perry has another good comment!

I get more interaction by interacting more. 

Top Groups can be found on the Groups page. 

Leave comments for others and most will check out your block and leave them for you. As far as groups. Bananatude

Write good content and leave comments on other rainers blog that add value to their post. Rinse Repeat Rinse Repeat.....over and over!  Come on over and join BananaTude. It's the most active group in the rain and has been for many years because we all have major tude....

The more you comment and ask and answer questions, the more people will start to check you out.  

My favorite group for finding great posts is Bananatude.  You can only post one per blog roll, so I think people save their best for this group.  I also like Addicted to ActiveRain, Bartender - Make it a Double, and WeBlog Anything (almost).  

When Bloggers with high point totals launch a blog post look at what Groups they sent it to (bottom portion of blog post)

Being active in Q&A helps, I think.  I don't post to too many groups anymore and can't really tell if it has impacted readership.

I recommend  getting to know some of the other Active Rainers...pop over to read some blogs and questions posted by others and share your thoughts. As others 'get to know you' you'll have more vistors that decide to venture over to your blog too...

I like Bananatude, which was previously mentioned and I think it is a pretty active group.  To get interaction, I think the topic has to hit a chord as well as be written in a way as to solicit opinions, etc.  Ask real estate agents their opinions or ask them a question and typically, you cannot shut them up!  (I say that with love, of course). LOL

Banatude is a great group, as is Photos, Old Farts Group.  If you want interaction you have to initiate interaction with other members.  Like everything else it is a two way proposition--give and take.  A

Write something that people are interested in.

It's all about the involvement of the individual.  

Reciprocation too.   

It doesn't usually happen overnight.  

If you go to the groups heading, I believe they do reflect the "top" groups by numbers of members.   

I like the thoughtful response provided by Nestor & Katerina Gasset.

Write interesting posts... be active with your comments on others' posts... answer questions.... etc. I don't pay attention to groups.

Be interactive yourself.

I have not used the group feature for years.

Dorie Dillard nailed this one!

Comment reciprocation is effective.

Many of us avoid the groups because many of them are not active. Use Facebook groups for better results.

Comment on others' posts and they'll typically return to your blog to reciprocate!  

Comments are down overall but to get interaction you have to give it. Give twice as much as you get for several days and you may get some new followers.

I think there are so many people here now that have great blogs that many readers do not stray form them

I use to use the groups years ago but have not for several.

Bananatude is the number one group, sure to produce some hits and comments.

The best way to get interaction on your posts is to be out there interacting, people will see you and find your posts.

Yes, you got right answers!

If you want to interact, then you have to interact.  You comment on my post, I comment on yours.  You follow my post, I'll follow yours. You've got to make yourself a known, viable entity here in the rain.  I don't pay attention to what other agents have in their groups. That's they choice.  I have mine.  Find yours?

Oh . . . and commenting on a reply is always a good way to make friends and get yourself noticed.  

Very simple, staying active, read and comment, on posts that you think are interesting and if you can write, compose engaging article often. I am contemplating contacting some of the best bloggers on  AR if I have questions. I may get the answers, or visit AR university!

Conclusion: Comments and posting engaging articles.

Always return comments, and make as many as you can each day.   Groups have lost their luster.

Always reciprocate comments.

Some of that will depend on the content itself and the interest to others. And perhaps asking a question at the end.

Actively participating by commenting on others' posts and following others will encourage them to reciprocate, and respond to comments people leave for you. Ask and answer questions so others get to know you. Engage, and others will engage

You have great answers already.

Answers all read the same.  You need step out yourself.  No different than being in public.  If you stand off to side few people will say hello or talk.  If you mingle and open yourself to people they will see and act on it.  Mark

Tori Toth - share these posts on Social Media. Works for me!

I'm not convinced of the helpfulness of groups for me because I do not specifically read from the groups. I think that is necessary to make a group useful. Which leads to my main point--be active. I think most of the people here with a lot of interaction on their posts built that following elsewhere. Comment loyally and provide help in the Q&A and people seem to interact more.

it must be intereting to the people your tyring to communicate with