Need help with this sentence..

The first example has all the required information but is difficult to read. The second example doesn't parse properly at all:

Now she is going to be late to Shelly’s cousin's, welcome home party.. Landon is back from Iraq on a month leave.

The comma after "cousin's" doesn't make sense. Cousin's what? House? Also, ".." isn't proper puncuation. An ellipsis has three periods (...), not two, but doesn't belong here.

The goal is to convey information clearly. Instead of throwing all this into one sentence, try breaking it up:

Now she is going to be late to the welcome-home party. Shelly's cousin Landon is back from Iraq on a month leave, and Shelly is throwing a party for him at her house.

kiss04bam said:

Now she is going to be late to Shelly’s cousin Landon's welcome home party.
Or should I have
Now she is going to be late to Shelly’s cousin's, welcome home party.. Landon is back from Iraq on a month leave.

Click to expand...

Try this: Now she is going to be late to Landon's welcome home party.

That works if you've already established that Landon is Shelly's cousin, that Landon is having a welcome home party, and that the character desires to be there on time. If you've established those things, then her realization that she will be late has some emotional punch.

Though you could fill in the details immediately after the realization, that gives the realization less emotional punch.

Dale

Now she is going to be late to the welcome-home party for Shelly's cousin, Landon.

I agree with Dale--it lacks any kind of emotion, and is just bland telling. It's okay if this sentence has to be telling, but make it do double duty. Have it also give some emotion or some characterization (just crappy off-the-top-of-the-head examples):

Now she's going to be late. Again. But it's only a welcome home party for Shelly's cousin. And he doesn't have to go back to Iraq for a whole month.

Now she's going to be late for the welcome home party. And Shelly will be pissed because her cousin is just back from Iraq and he has to go back in a month.

Now she's going to be late. But what better way to get Landon's mind off Iraq than to make a grand entrance at his welcome home party in that strapless sun dress.

How about this:
"Now she is going to be late to Landon's welcome home party."
"Who's Landon?"
"Shelley's cousin, he's coming home from Iraq."

kiss04bam said:

Now she is going to be late to Shelly’s cousin Landon's welcome home party.
Or should I have
Now she is going to be late to Shelly’s cousin's, welcome home party.. Landon is back from Iraq on a month leave.

Click to expand...

The second one is sort of a mess for reasons previously noted. So I'll focus on the first one. Here's a simple question: why on earth do we need to learn the name of Shelly's cousin in this sentence? We probably don't. There's no reason I can think of that his name couldn't be revealed in the next sentence, or even a good deal later when she gets to his party. So since we don't need to know his name here, you can just say "...to Shelly's cousin's welcome home party." The sentence becomes easier to read right away.

So there's the basic rule when you're trying to streamline a sentence: ask yourself, do you really need ALL that information RIGHT NOW? If not, trim whatever information you don't need. And just watch how quickly the sentence improves.

The problem is that it's boring from the get-go. Why not try something in this vein:

"Darn it! Now she will never make it to Landon's party in time!"
"Landon? You mean her cousin?"
"Yeah, he's coming back home from Iraq today. She really wanted to see him."

Still not great, but I hope you know what I'm getting at.