To improve your interpersonal skills, the most important step is to address the issues that prevent you from initiating a conversation with someone. It could be shyness, discomfort around authority figures, or lack of content. Knowing the reasons behind your hesitation could help you understand your areas of concern.
To be able to start a conversation and hold it pleasantly over a length of time, you need to be really interested and involved in the conversation. That will only be possible if you have a genuine love for meeting and knowing new people.
Having a collection of conversation starters will help if you have a few witty lines and introductory lines ready that will help you in all occasions. Simple gestures like smiling and then waiting for a return smile before introducing yourself, commenting on something in the vicinity, commenting on a shared interest are just some of the starters that can get the other person in a conversational mood.
The secret behind making a small talk is to relax. The more relaxed you are while talking, the more natural you will sound, and the more interested the other person will be in listening to what you are saying.