(mannnn I have the same problem as well sobs)

If it's within a chapter, I think there's no issue in pulling a "a couple week later", since it's easier that way to keep the flow of the story. If it's between chapters, the easy way out, which is what I'm doing on my novel, but for different reasons, is putting the date on the start of the chapter and moving on, since you don't really focus too much on the past in real life. If you don't want to do that, just keep moving on with the story, but reference the passage of time with the environment interactions between characters (example, in the previous chapter, char A invited char B to meet up with C, D and E. Next chapter, C and D show up and B mentions E is missing). Besides that, I can't really go further, as I usually just power through writing when I get in the right headspace and not think about it too much

I add it in a way that fits whatever is happening in that exact moment. For example, if two people were at a bar and the timeskip brings them to a couple weeks later, I try something like this: "She hadn´t been that embarrased in years. It was not like her to talk with strangers about her life. That, at least, she could leave up to as merely having one too many drinks. But giving out her phone number to someone she had just met? That was a whole new level of risk she wasn´t used to experiencing. Still, two weeks had gone by radio silent from that unusual girl´s side. Perhaps she had forgotten about her, perhaps she had been as drunk or even more than her and had claked up their convo as just some silly flirting. Maybe, just maybe, there was nothing to worry about". English is not my mother language, so I apologize for any mistakes in writing. But treating the pass of time as something "normal" and part of the story usually helps the reader take it as such, as something that doesn´t feel bizarre or out of place. Even then I´m not a professional by any means, so take my words with a grain of salt

Hmm I'm no professional, but in most of the books I've seen, they usually don't directly address the time skip. Instead they (if this story had characters) use the characters as a form of communication to convey to the reader of what amount of time has passed. Ex: "The morning sun against the dewy leaves of my house plant always give me a sense of happiness, I can't believe two weeks passed by in the blink of in eye." Basically a inner monologue, I'm sorry if this doesn't match what you were trying to ask, hopefully it helped in some way!!

For a more like subtle way to do it you could use seasons, if the timeskip is long enough, like in the previous scene establish that its summer and then in the next one say smth along the lines of "autumn was beginning to creep in, winds blowing a little colder but not quite enough to warrant a jacket just yet", smth like that? or alternatively if there's dates established, u could use those? U mentioned u were writing a slice of life, if there's any sort of date (like this is in a school/college setting or theres an event coming up) u could go from one scene saying "the event was a couple weeks away" and the next going "the event was a couple days away" smth along those lines yk?

When it comes to this kind of thing there's a range of ways to do it and it can really depend on what comes before it. Truly the phrase of "There are as many ways as there are people". In this case if it's a modern slice of life then depending on the story content there's some typically options. Is it a school romance? Mention how so many new assignments absorbed the characters time as they rush to get through the weeks of heavy projects. Or even how a holiday came by and people left to go see family for a bit. Even something like a rainy season that kept most people indoors, as your character either enjoyed or lamented about the rains interference. Theres a lot of ways, and don't worry if you don't get it right out of the gate, writing is always evolving and getting better needs doing in the first place to develop it. I have tons of faith in you harun!!