The web page will have good LCP if the largest contentful paint loads within 2.5 seconds. Mostly this can be done by optimizing the loading for media such as images, iframes, videos, etc. If an image takes time to load, you can go for optimizing media, convert it to webP format, check the media size used if it is larger than what is needed, you can reduce the size of media both file size and the dimensions.
Google Pagespeed Insights will consider the page LCP good if it is loading under 2.5 seconds. If it takes more than 2.5 seconds, then it needs improvements.
It will be again a good time to reconsider the content structure of the page. Because sometimes we will not need bigger images in the webpage above the fold. You can surely have bigger images but putting them below the fold will make web page render faster. The image sliders, the iframes can be loaded below the fold so the initial web page renders faster giving the page good LCP.
Here are some resources: