That's what I also do, intertwining the main plot with subplots and revealing some details about the main plot. I just wonder if I could do a subplot to not directly tell information about the main plot... but maybe use it later to make sense etc!
I'm not a beginner writer, I'm just somehow lost cause I always strive for some creativity and originality and I think that makes me somehow lost in the idea of plot and not the execution which is rather crucial. Sometimes just talking about the overall writing tips makes me think differently about how to write stuff 
@XzynderVexymous That's why I want to include subplots, I love complicated stories but I don't like when the general plot is lost due to some pointless character arcs. Marvel cinematic universe is a huge one at this point and yes, we can see that they throw some general information and tid bits about a "main story that connects universe" so I get the idea.
In my story I'm building subplots based on characters mostly, I've got for example: cultural issues, conflicts like war/injustice, religion etc aside from the main plot. I'm just looking for a fresh look at the whole subplots thing!
@joe_galindez It's maybe because we mostly strive to make main plot stand out and be polished, although I think that a good story is a story when we care about many issues and the main plot/goal.
@Damatris So do I, to put is simply: secondary character = subplot that expands the main plot. The question about making a story longer or slower paced was actually about some more loose chapters (example: a more comedy or refreshing arc contained within one-two chapters, like the popular "we're going to the beach!" thing, but when we still find something out about the characters or a tiny information about the subplot/main plot). And I was just wondering how to write a good subplot for readers to enjoy actually, not for the sole reason to convey information everytime (or like maybe a mis-information, that would be great).