Over the years I have found the following guidelines and tips to be helpful in creating intimacy and comfort in the small group setting.
Be in prayer. Don’t try to do this on your own. Bring your people, your preparations and you fears before the Lord.
Be prepared. If you’re leading a group that is doing a study together, have it done ahead of time. Know the material well enough to have some supplement questions prepared in case conversation falls flat. If you’re leading an Embrace group have your questions printed out, cut and on the table ready to go before your group arrives.
Demonstrate vulnerability. If you as the leader are not willing to show some growing pains and weaknesses in your life no one in your group will either. Set the standard.
Learn the art of silence as you lead – Don’t occupy the time with your voice. Give the group a chance to process the questions, and the open quiet space to get brave enough to speak up. After reading a question, I challenge you to slowly count (in your head) to 10 -15 seconds before speaking. Scary I know! But if you rush into the silent moment with commentary or answers doing so may deliver a message to group members that this isn’t their time to share, and it’s just for the leader to teach. Typically small groups aren’t supposed to be that way. Leaders should truly facilitate, create the environment and guide the group through the time, not teach the entire time.
Be faithful and honoring to who does show up. Sometimes we want to cancel when we know many group members can’t come. But canceling should be avoided as it may deliver a message to those that are available, a message that says meeting together is only worth it if so-and-so is there. Honor those that are available, demonstrating that you value your time with them. Also remember, that not everyone will be able to be there every time, but it’s still important to meet.
Don’t force it. If the conversation is just not taking off, don’t push it and don’t insist everyone answers every question. When things just aren’t working that day, just casually say, “well let’s move onto something else.” This is where being prepared comes into play. This could be an opportunity to try another community creating activity. One I suggest is using out prayers of intercession resource.  Again, just casually say, “well let’s move onto something else. I’ve been wanting to share this unique prayer technique with your guys.” Hand out the forms and give instructions. See the link above for instructions and the print out (print out ahead of time just in case!). After everyone gets their original form back, invite anyone to share about their request. Again, practice the art of silence and give space for someone to share. Count to 15! One brave soul may be the one that leads your group into a special and tender time of sharing.
A few minor but significant things to keep in mind!

• Keep the group no larger than 8, any larger people will get lost in the group.
• Sit in a way where everyone is facing each other, whether in a circle or around a table. If there is a ‘second row’ because there are so many people it’s probably time to split and create two groups.
• Don’t become discouraged when there aren’t any ‘wow’ moments that day. Sometimes there will be awkward moments or days when it’s just two or three of you, or days when you didn’t feel the group connecting –  but don’t give up, that is not a reason to declare ‘this isn’t working.’ 

Keep trying, praying and trusting. If you’re pursuing Him and acting in obedience, He’s got you right where He wants you. “And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ.” Philippians 1:6
Here’s a link to a few more helpful tips.