I'm in need of some tips and or advice plz?

My gf and I have been going out for a month now we are at a long distance relationship at the moment. So basically trust and communication are very key that I understand. We pretty much talk/text each other everyday since we've been going out so we pretty much talk a lot but at times we both find that we both have ran ot of things to say or talk about. We pretty much talk about the usually how our day is and everything in that category and then our convo's get into heavy subjects like plans in the future and what we both want (this in which is each other). But I really want this relationship to last a very long time she really does mean a lot to me and she said also likewise. I just don't know what to do or what to say anymore and I don't feel like bringing back the same subjects over and over again cause I see its getting tiresome. So basically I need help, tips, advice or anything or that matter of new things to say or I should do when it comes to this