Depending on the severity of your "ums", this is a facet "normal people" may need not perfect (or even need to work on). This article is the minimum strategy,

Depending on the severity of your "ums", this is a facet "normal people" may need not perfect (or even need to work on). This article is the minimum strategy, the 80% of a good presentation. Ums are a detractor but not as much a one as poor product knowledge or mechanical storytelling.