Here are some things I'm learning about Fiverr, the hard way:
1. Make sure you're good at whatever you're offering, and that your video shows it. I seem to have done OK on this as soon as I put up my first voiceover gig, which has gotten a lot of positive response.
2. Make sure you're comfortable with what you're doing. I have recently pulled my video gig because I was being asked to lend my face to things that I didn't agree with; one customer, without asking first, asked me to say that I was a woman. Sorry, no.
3. Don't accept offers to do anything outside the scope of the gig. If, for example, you do voiceover, don't offer to put music behind it. If you're good at this and want to do it, offer it as a separate gig, if you can do it reasonably for $4 net, or as a gig extra, making sure you charge enough. Extras tend to get out of hand.
4. Get all the information you can before you start the gig. And if the buyer doesn't give you what you need, do exactly what he or she gave you, no more and no less. You can't produce high-quality output with low-quality input, and it's the buyer's responsibility to tell you what you're expected to deliver.
5. Charge a fortune for fast delivery. Really. $20, $30, or even $40 is not out of line. It's doubtful that you make your living from Fiverr alone, which means you have a life. Setting that life aside in order to deliver an order that, after fees have been paid, might net you $12 is not worth the stress. If someone needs it that fast, they will pay extra or go elsewhere. Either way, you win.
6. Realize that all the precautions you're taking won't protect you against unthinking or abusive customers. And, unfortunately, Fiverr is more buyer-friendly than seller-friendly, as far as I can see. There is no way to prevent a demonstrably abusive buyer from buying from you, and canceling an order, even if it is because the buyer asked for something quite unreasonable—or totally ridiculous—can count against your overall ratings, increasing the pressure to deliver orders even when it is not in your best interests to do so.
I'm sure I'll be adding to this list as time goes on, and the only reason I've posted it now is that I've just had a buyer who expected a lot for the money, and gave very little information up front. I've already had to re-do a substantial amount of work, and I'm not happy about that.
So, after a break, I think I am doing some editing to my gig. But probably not today; I have a rehearsal tonight and I need to study my lines.