Proper use of keywords in CL ads?

The absolute best practices involve creating 2 - 3 ad versions, 2 - 3 ad titles. Sprinkle in your target keywords both into the title and into the ad body in a natural fashion. Keyword stuffing is explicitly forbidden by the Craigslist TOS and will get your ads flagged.

Try to avoid verbose, wordy ad text that reads like a novel. Instead, use bullet point items that have your keyword naturally integrated. The theme of the content in those bullet points should clearly describe why your target audience should choose your product/service over your competitors.

Appreciate it, will give it a try. Next, some CL posters have told me they using coding which does not make their many kw's visible in the ad, this way the competition doesn't see your kw's and also allows you to use many kw's outside the body of your ad, does this work or should all kw's be seen within the body of the ad?

The question you have to ask about their keyword coding is this:
At the risk of increasing your flagging chances, will their "embedded keyword" strategy provide any additional benefit rather than simply distributing your target keywords across 3 of your own ads that have all your keywords just naturally mentioned?

Sounds to me like they are trying to get into a grey area when you can accomplish the same thing in a way that won't risk having your competitors flag your ads and that will attract more client eyeballs. Bottom line is you want more clicks and calls and to be found for your keywords. You should always opt for the path that minimizes flagging risk.

My main point is this
You want your ads to be visible for your keywords when your target audience plugs them into the CL search box. If you can accomplish that by naturally sprinkling those keywords into your ads and titles, why would you consider any other strategy? Craigslist has very sophisticated ad filters which are constantly evolving to shut down "loopholes" like this invisible kw approach. If you are intent on building a compliant campaign that you can scale up, build it on a solid foundation that doesn't risk flagging by either your competitors or by Craigslist.

Temporary "invisible keyword" strategies seem short sighted and introduce unnecessary risk

Ok, understood now, normally I will see ads like this with a string of kw's underneath the ad, is this also wise or instead of placing all kw's in a string then are you saying it will best to take each of those kw's and use them in the main content?:

I enjoy fixing computers, when people call me mostly, I already know what is the problem and my rates are very cheap compared to any competition out there. I have a computer degrees and certifications so i know what I am doing. I can fix your computer 24 /7.

some items that I love doing all the time

PC, Computer, Laptop, Desktop, home networking, office networking, wireless routers, switches, repair, data backup, data restore, tune up,upgrade, service, software, hardware, Laptop Screen Repairs, Windows Reformat, iPhones, iPads, Tablets, Cisco, dell, hp, compaq, gateway, apple, Acer, Sony, Toshiba, Samsung, IBM, Lenovo, Asus, Fujitsu, emachine, NEC, Sharp, Panasonic, windows 7, XP, Vista, windows 8, virus removal, email, internet,Mac, OSX, leopard, lion, operating, system, OS, IT, information, technology, re-install, installation, blue screen& start-up problems, broken screen, no sound, no video, no internet, Mac OSX, Mountain Lion, Lion, Snow Leopard, Leopard, server, virus scan, antivirus, RAM installation, sound card, video card, motherboard repair, cheap, flat rate, keyboard replacement, optical drive replacement, CD drive replacement, DVD drive replacement, hard drive replacement, Computer Tutoring, dv6, parts, repair, screen, keyboard, pavilion, Microsoft Office, support etc.

Use the keywords in the main content. Stringing keywords together is an invitation to flagging

You should reflect the keywords as your target audience would type it into the CL searchbox

I will try my best, really appreciate the help, tthanks!

Yes . It is possible and this is smart way too. But don't push too many keywords in your content. If you do so then it'll bring flagging problem.

join the club. my bitly links will not post so i usually space it out. not sure what else to do but i would like to know.

Many of the canned post formats coming in from outside services didn’t work on mobile devices (where Craiglist draws a significant portion of its traffic). Some posts on Craigslist were just a collection of links, bouncing traffic off the site.