After selling 8 cars in the last 3.5 years, I think I've acquired a few skills advertising vehicles on Craigslist.  
I'll give you a quick run-through of how I'm going about selling my brothers car for him.

Here's the link if you're looking to buy a car :)
https://portland.craigslist.org/clc/cto/d/1999-honda-civic-ex-one/6505704203.html

My basic tips {in bold below -- 6 points} Italicized is the actual Craigslist post:

{1.  If the car is ugly (which my brothers car is, and two other cars I've sold have been), keep the advertisement light.  People are not going to buy your car because of it's looks, rather they are interested in the features and drivability.  Tell them a story about the car and they'll feel like it has a soul... or at least that's my idea!}

 Do you want a car that's light on your wallet, high on your MPG's and brings the ladies, men, or however you identify (this is Portland) to their knees? Look no further than Helen (yes, that's her name).

I sold my brother a 2009 AWD Subaru Legacy, so he is reluctantly deciding to sell his 1999 Honda Civic Ex, Helen. I have been driving Helen for the last month while my truck is in the shop. I can't believe how much I've missed having a fuel efficient manual as a daily commuter.

{2. Explain why the car is being sold, if you've got a newer car that's a pretty good reason.  Maybe you needed a larger vehicle because you just found out you fathered triplets on that one-night stand you had 9 months ago, whoops!}

The last two tanks:
60% Stop/Go City - 40% Highway driving = 34.8 MPG
80% Stop/Go City - 20% Highway driving = 32.7 MPG -- SERIOUSLY, this car is itching for more miles!
This current tank I'm about 2/3 Stop/Go City and 1/3 Highway and I'm on course for another 33+ MPG tank despite snow driving and letting her idle and burn off all the snow.
She's primed and ready for another 70k+ miles.
Several years back I got 41 MPG in a tank. Freeway driving you're basically guaranteed 35+ MPG if you're doing under 75. City/Freeway driving is in the 32 MPG - 35 MPG range.
{3. Sell the best feature, in this car it's the efficiency.  These MPG's are legit for a car that's pushing 20 years old!  Beat it into the buyers head!}

Pros:

**One family car, only owned by my dad and brother.
**Regularly serviced and maintained.
**My dad drove this car for 175,000+ miles, he babied the shitake mushrooms out of Helen. Seriously, he is the guy you pass on the freeway wondering how he ever gets to work on time because he is driving so slow.
**Clutch was replaced in the last ~10k miles.
**Radiator and hoses replaced in last ~10k miles.
**Brakes replaced in last ~5k miles.
**Clean Title
**Great commuter car, great car to teach a teenager stick on (basically a brand new clutch)
**I sell her to you with a full tank of gas, when was the last time someone did that for you?
By the way, that full tank is good for over 400 miles, if you're trying to leave the state fast because you have a crazy ex girlfriend, you're wanted by the police, you don't wanna pay that child support because the kid might not even be yours, or you'd like to go on a pleasant road trip to Yosemite with your grandma -- this is definitely the car for you!

{4. Make your "Pros" list bigger than your "Cons".  Except I don't like calling them Cons, I use "Areas for Improvement" or something with a positive spin.} 

Areas for Improvement:

**She's got some dings and scratches, which basically say I've lived a good life and got to see a lot of highway miles.
**Paint is peeling on the hood, pretty sure the rustic look is in right now -- you've seen the chicks wearing ripped jeans right?
**Small crack on the top of the windshield (won't get any worse, not in drivers line of sight)
**Slight tear in drivers seat (my recommendation: get a bad@$$ Batman seat cover)
**Back right speaker is a little scratchy
**She sips a little coolant -- not like she's trying to get crunk. More sipping like a sophisticated upper-middle class broad that went wine tasting and didn't even get buzzed. Hasn't been a problem, because she's not a coolant-holic.
** Tires need replacing in the next 15k, they did well in the snow but may be ready for a swap next winter depending on your usage.
**But don't low ball me/my brother. Because if he doesn't get the price he's looking for, I'll just buy it from him.
{5.  I like to keep my "Areas for Improvement" light and fun.  Sure, the car is not perfect, but if you're looking in the price range your main purpose should be finding a car that runs well.  Decide what your average consumer is looking for in this vehicle and be honest about the vehicle.  Don't waste your time, or the buyers time by excluding key details.}

The Backstory

This Honda Civic was bought by my father in the great year of 1999, when everyone thought Y2K was going to end the world. Well everyone except my dad, obviously, or he wouldn't have spent all his hard earned drug money (he's a pharmacist) on this car.
If you're looking for street cred, you can say this car was owned by a drug dealer, he was pushing the most bags in the NW! (He was the manager of Providence Home Infusion at the time (IV bags))

My father was going through his midlife crisis, and what car better to satisfy his need for fuel efficiency (and a little speed, you know 50 MPH in a 60) than a manual teal green Honda Civic. He named her Helen.

He had Helen for about 12 years. It was hard for my dad to sell Helen to my brother, but a more fuel-efficient vehicle came along (the Prius). My dad regularly maintenanced and took great care of Helen and my brother has done the same for her.

I am helping my brother sell Helen, he's busy with both school and work right now and I owe him a favor since I've borrowed the car for almost a month.

I'll send the VIN to interested parties. This title is cleaner than a babies bum after a warm bath.
I don't think you'll find a better, more reliable, efficiency mobile at a lower price. My dad and bro have all the maintenance records that we will gladly dig up for interested parties. 

{6.  Especially on crappier cars, I like to give them a soul.  This car had been in the family for 19 years, she has a name, she's been through a lot.  What's special about your car?  Has your car ever farted at you on a special date?  Did your car save your life?} 

I'd love to hear your best car story.  Or what's the best name you've ever had for your car?

My first car: a loaded 1994 Purple Ford Crown Victoria LX was named "Laquisha Shaniqwa Love".