Having all of your material before you, with notes made in the margins to remind you of certain points or an outline, saves time. If you have multiple things to dictate, start with the most urgent dictation first. And ensure that your transcriptionist knows that. Try to anticipate the problems she might have as she transcribes your material. Doing so could ultimately save you big money.
Background Noise:
Eliminate as much background noise as possible before starting. It is amazing how even footsteps or someone else moving about in the room can detract from the quality of the dictation.
Be Natural When You Speak:
Picture the transcriptionist is sitting before you, and speak as if you were having a natural conversation. Keep things out of and away from your mouth, i.e. a pencil, cigarette, or gum. Enunciate clearly, and
speak at a steady pace. Speaking quickly to save money often defeats the purpose, especially when an accent or background noise might interfere with the transcriptionist's understanding of your words.
Begin Dictating:
Start with your name.
Detail any specific stationary instructions, letterhead, form, etc.
State whether it is an Inter-Office Memo, a report, a company letter, verbatim transcription of a focus group, etc.
Include reference #'s, client #'s, case #'s, etc. at the beginning of the dictation.
Specify how many copies you will need.
If your transcriptionist is to distribute the material, specify how she should distribute it; i.e. CC's or BCC's for Email. Or mailed, will it be Certified, Registered, Express, normal mail or courier service such as UPS or FedEx. Do you require a delivery confirmation?
At the end of each dictation, say "End of This Dictation."
As you dictate, specify punctuation to be used - periods,commas, quotation marks, new paragraphs, em dashes, indentations, etc.
Avoid empty spaces during your dictation. If you need to stop to collect your thoughts, answer the phone, etc.,pause your recording. Long periods of empty space cost you money.
When speaking names, spell them out the first time you use them. The same holds true for technical jargon, foreign words, or anything else the transcription might not know. Most transcriptionists have reference books that help, but the dictator can speed the process up considerably simply by alerting the transcriptionist to new terms and names.
Dictation for Printed Forms:
Keep a copy of the form in front of you for reference. Dictate in logical order of the form, top to bottom, left to right.
Start with your name. 
