New player - Looking for late game advice!

Hello,

First post on the boards here and I just started playing about a month ago. A little background, I'm new to the MOBA scene and have tended to be more of a console gamer over the course of life, but I have experience playing Warcraft 3 and a variety of other RTS games on PC. I feel I usually tend to pick up games fairly quickly (at least compared to my friends). I feel my mechanics have come along over the last month, but what I've been noticing lately is that either myself specifically, or my team as a whole starts off strong by gaining kill, tower and gold lead, but end up throwing the match once scaling into late game.

Now, I am aware that I tend to play champions such as Darius and Jayce that don't seem to contribute a ton in the late game, but I still feel like my team should still not be blowing such big leads. I'm talking 7k+ gold leads. As soon as the late game 5v5 team fights begin, thats when I begin to notice the shift in momentum and lack of communication.

I'll look at the gold graph at the end of the game and I'll see us with the advantage all the way until the very end. I know that I myself can significantly improve when it comes to learning the Macro part of the game. When I watch pro games their decisions make sense to me, but trying to apply these things in Solo Q seem to be a struggle. Communication in normal games tends to be a struggle and quite honestly I don't feel confident shot calling at this point.

Again, I still have games where I absolutely get rocked in lane, but I feel like I tend to contribute well when it comes to damage to champs, kills etc. So...what can i do to help prevent this? Maybe its worth noting that I mostly play top lane. My first thought was maybe, I need to focus more on snowballing objectives even if it means losing my life for a turret? Any advice would be great!

Thanks!