Limit the Phone Usage
On the day of your date, limit the number of texts and messages you exchange. You can beg off with an excuse of being busy if need be, but try to avoid too much chatting unless you are going on a first date with a longtime friend with whom you have never had trouble making conversation. It can be tempting to text all day as you get excited about the date, but by limited how many messages you send, you will not run out of things to talk about before you ever get to your date. There is also some truth to the idea that absence makes the heart grow fonder. After a slight slump in messaging, your date will be even more excited to see you in person.
Once you start your date, keep your phone in your pocket. If you pull out your phone whenever the conversation lulls, you will never start talking again. Besides, ignoring the person you claim to be interested in dating in favor of your phone will just about guarantee that there will be no second date. After all, they clearly did not hold your interest.