It's all about your frame. You need to be less focused on entertaining them and more focused on amusing yourself. Do things just because they entertain you. You're trying to suck value from the interaction rather than providing it. Just act like you two are in 4th grade again. Act goofy, throw pieces of paper at their heads, tease them, steal their drinks and start sipping on it, make whatever they say into a weird pun, harp on them when they act weird or awkward, etc. etc...
In the long term, the best way to improve this is to simply go out and keep opening sets over and over until you simply don't care any more. I would also read up on some game stuff. RSD has some solid stuff. Dont overthink the interaction. Literally take a breath, calm down, take a sip of your drink and try to relax and enjoy being in the moment and chill.
In the short term, here is a few things you can try:
EJECT - When you feel the energy start to drag, it's time to eject before the interaction is ruined. My line: "well it was good talking to you, but i need to be getting back to my friends". I've gotten into the habit of simply excusing myself when i feel like i'm running out of things to say. As long as it's not a huge bar/club with hundreds of people, the chances are high that you'll bump into them again. You don't wanna be the guy standing there sucking value while they're thinking "sh!t, i really hope this guy goes away pretty soon"
Place the burden on them - One thing you can do is that when there's an awkward silence, just simply look at them expectedly and act like they're the ones being awkward and antisocial. Girls are super talkative creatures, and IF they are interested, they will ALWAYS continue the conversation, so long as you don't sit there and non-verbally act like you're the one messing up.
ESCALATE - Night game is a giant joke and half of it is simply being super aggressive and escalating. You should never be sitting there for 20 minutes talking about bullsh!t without starting to escalating physically and initiate kino. Confident escalation is probably the most attractive thing you can do. Any guy can sit there for 15 minutes talking about what he's studying. It takes a playa to make the right confident moves and push towards the lay.
But, what Mauser said is true. Approaching random girls who didn't give you IOI's is fine to just get the juices flowing and warm you up for your other sets, but you're going to waste SOOO much time on bad leads if you just open any cute girl. You will have more success opening the one girl who made eyes at you over the four sets who it's obvious don't really want you there to begin with. Stop plowing and focus on good leads. The worst part about opening random girls is that it can kill your momentum because the rejections can start to take a toll on you.
Don't WANDER. Don't be that guy who drunkenly wanders around the bar scoping out girls. post up at the bar, sip your drink, and open the hot girls who come into your immediate area to buy a drink. That way, they essentially came to you and you're just chilling where you were chilling already.