If you don’t have a product or service that enough people need or want to make it worthwhile (or could be made to want), you won’t prosper.
If the costing and pricing of your goods or services is off, you won’t prosper.
If you can’t locate “suspects” to contact and promote to, in order to see if they are prospects, you won’t prosper.

If you don’t know what to say to suspects once you find them, so you can identify or isolate the prospects among them, you won’t prosper.
If you can’t respond properly when prospects identify themselves by expressing a reach or interest for what you offer, you won’t prosper.
If you can’t determine the actual needs & wants of your prospects, you won’t prosper.
If you can’t make a good sales presentation to prospects, you won’t prosper.
If you can’t overcome objections that prospects have, you won’t prosper.
If you can’t “close” prospects, you won’t prosper.
If you can’t or won’t deliver what’s promised after you close your prospects, you definitely won’t prosper.
Your marketing programs, activities, events, methods and procedures are only as strong as the weakest link in your whole marketing “chain.”