Bearing in mind I was brought up to believe small talk is pointless, I've had to teach myself how to do it.. this is my technique!
Ask people about themselves. Standard topics include "what are you up to at the weekend?/what did you get up to at the weekend ...Ooh lovely" "wow it's been cold/warm/etc today! Do you think it's going to get colder/warmer?" "What are you watching on Netflix/Prime/did you see X what did you think?"
Topics to avoid include the obvious, sex money politics, also work. No one likes talking about work. Even if they love their job. Just don't!
If they have DC ask about them. "How's X doing with school/hobby Y now?"
Obviously only ask questions you're prepared to also volunteer info on yourself, I find it really rude when people ask a barrage of questions and don't say anything about themselves.
Basically if you think of a conversation as tenmis you won't go far wrong. Ask them a question, listen to their answer, volunteer some info yourself, if they ask you something answer it, then ask them the same thing or if they don't ask anything, ask another question etc. Try to get it 50/50 length of time talking for each person, avoid going into too much detail or speaking for too long in one go, focus on batting it back to the other person.