Gig Description is the first long step you cross to catch the success, why I used long step for description because every customer will observe your work by reading your description you must shine it using the following things.
In the first paragraph of your description you have to tell how customer will be beneficiary if he order your gig.
Second paragraph you need to mention about your work history you expertise.
Third you have to tell about service your are providing what he will get in $5, you can also mention you have Gig Extras as well.
Fourth you need to include your portfolio links, many people thing fiverr dont allow external links in Gig description but that’s not true, you can include link of your portfolio without http.