Don't send clips of work you've self-published or posted on your own website. And remember, bad clips are worse than no clips at all. It's best to send clips that are relevant to the proposal, if you have them. If you don't, send samples from your most prestigious publications. If you have no clips, don't despair.
Most editors consider the merits of a query first and the clips second.
If your query is strong enough, the absence of clips shouldn't be enough to trigger a rejection, unless the publication works ONLY with published writers. Then, send a polite follow-up. Attach a copy of your original query, so that the editor won't have to search the files for it. If you still hear nothing after another 3-4 weeks, consider a polite phone call. The ability to write a good query is one of the most important skills in a writer's toolbox.