How to be more comfortable with people?

I have a few certain friends I talk to regularly, and when we have conversations they always feel so natural. I never have to think twice about what I'm going to say. The thoughts manifest instantly, and the conversations always feel so real. Then I have a few other friends that I talk too, and when I text them our conversations always feel forced. Im always uncertain about what to write and how to respond at times, and overall I just have trouble maintaining a stable conversation with them. Is there something wrong with me? Is there anyway around this? I just wish I could talk to these people as naturally as I talk with my regular friends. Its just sometimes I meet people that I REALLY want to get to know, and due to my inability to sustain a conversation, I always run out of things to say and I end up ignoring them because I never know how to talk to them and I don't want to make myself appear like a jackass.. I just wish it wasn't like this. I used to be more capable at talking with people. I used to be able to be super comfortable with anybody within a matter of days. Now look at me. I barely am able to make sufficient conversation with people I would love to get to know. I honestly don't understand the psychology behind it.. It's just so strange.. Thanks for reading guys.. Hope somebody can help me fix this aspect of me..Maybe my ability to communicate with people has just decreased because over the last year or so I've spent a lot of time isolated and not really open with anybody as much....i dont know.

I feel you on this. I have (and continue to) struggled with this exact same thing and I've made some headway so I do have a little advice.

1. Conversation begets conversation. If you want to talk with someone you need information about them. If you find it difficult to talk to someone the conversation is short, which means you gather little information about them. So when you see them later you don't have much in the box of topics to draw from. This means you have to improve those initial meetings so the snowball effect can begin.

2. Loosen the restrictions on self editing yourself. Say the things you think are stupid if it relates to what is being talked about. Poor conversationalists often over estimate how "brilliant" their responses must be to pass as acceptable conversation. When people drink they often have much better conversations. Alcohol inhibits your mental faculties but why that doesn't result in poorer conversations is because people self edit a lot less (a.k.a say what's on their mind).

3. Don't give up so easily. There was a time when I would just walk up into conversations listening and adding my 2 cents in and it wouldn't engage the person/group so I would just tell myself I sucked at conversations and walk off. Sometimes you need to throw a few balls before you make a completion metaphorically speaking.

4. You have to crawl before you can walk. There will be times when you will show conversational deficiencies and people WILL notice. This is where you have to choose your future progress over your currant persona. Growing pains so to speak. It can seem a hefty price to pay for the ticket but the destination is worth it.

5. Don't be a self fulfilling prophecy. If you woke up tomorrow with selective amnesia forgetting all the social interactions you have ever had, your beliefs about what kind of conversationalist you are would be wiped clean. You would have a clean slate on what is you identity in this subject. No pre-concieved notions of what you are or are not capable of. Adopt a positive yet still realistic view of your conversations. If you have ever had a time when you conversed well in areas you usually do not simply believe that your next conversation MAY be one of those.

6. Take the pressure off. Have you ever heard the saying, "I can't hear myself think." This is usually because there is some distraction interrupting ones train of thought. Pressuring yourself to make it "work" causes distracting inner dialog. Thinking and responding is hampered when you have a inner voice asking how are you doing so far and what are the consequences.

7. Allow for silence. Most people fear periods of silence in conversation. They will throw anything out there just for things to not be awkward. I once saw advice where it said silently count 3 seconds in your mind after a pause from the other person. I thought it sounded ridiculous until I tried it. 20 minute conversations would happen where the other person never seemed to notice I was saying next to nothing.

8. Don't wait for your turn. One of the most common bad habits of conversation is that people get some "awesome" story that is relevant to the discussion and all the sudden they are anxiously waiting for the speaker to shut up so they can impress with their glorious tale. Let your story go. You already know it. It's a re-run. Listen to the speakers original (to you) content. Then if that more than 3 second awkward silence arrives guess what? You have a huge back log of relevant stories to re-facilitate the conversation.

9. Find a way to be interested. Sometimes people talk about things you aren't particularly interested in. Your faking interest perhaps. pretend someone was going to give you $500 dollars if you could find some related tangent from what they are saying that you would GENUINELY be interested in hearing. This keeps you from faking interest which socially aware people pick up on.