Like most people, I start by looking at
(of course, a) you look at yourLJname/friends and b) there's almost always a friends group filter too...)
(your number may vary...)
and so on, back in time.
So, to take an example from today's reading, you see the aftermath of a breakup before knowing that a breakup has happened.
Reading news in this way can be interesting - I once looked through a pile of year-old Guardians and hindsight meant it was both possible and fascinating to spot the small beginnings of what became big stories.
But normally I prefer to live life forwards.
And as I say, that's currently difficult with LJ. You can make a guess about the right value for ?skip= and iterate to the right figure, then start reading 'next 15 entries' until you hit 'now'.
But if someone on your friendslist posts between loading page n, reading it and loading the next page n-1, you will miss an entry! The bottom entry on page n-1 will become the top entry on page n and you'll never know (without looking at page n again).
Let's say it again: LJ needs an offline reader (OLR). You'd download all the entries you hadn't read, then the OLR can present them to you in any order you desire.