1. Open Ended Question
Ask open-ended questions (Why, why, where, how, etc.) instead of affirmative questions (Yes/No).
Open-ended questions give you and others the opportunity to branch off to other subjects as opposed to Yes/No questions.
2. Make Eye Contact
But don't stare.
Avoiding eye contact shows a lack of confidence and will be interpreted by many as disrespectful.
On the other hand, staring will make them uncomfortable.
3. Avoid Filler Words: Mmmm, Uhhhh, Uhm
Filler words like Mmmm, Uhhhh, and Uhmmm show hesitation and lack of confidence.
If you really must take a pause while you are talking, just be silent for a second without using filler words.
In the beginning, it will seem hard and awkward but you will get used to it over time.
4. Unsestand Body Language
Body language helps you understand the emotional state of the person sitting before you, are they stressed, calm, happy, sad, etc.
Use it as a hint to steer the conversation based on the demands of the situation.
Body Language Basics: 19 Tips To Help You Understand Others Better
5. Conversations are bi-directional
Asking questions makes others feel like they are in an investigation and will slowly feel uncomfortable as they are the only ones providing information.
Too many statements make them feel unimportant as if it is all about you.
Aim for a reasonable balance between questions and statements.
6. Branching Opportunities
It is hard to come up with topics to discuss out of the blue so the best way to having a long conversation with someone is to branch off from ongoing topics.
Find sub-topics within the big topic currently discussed.
Equally important is to give others a chance to branch off from your statements.
Tell stories that are both lively and rich that make others want to know more.