Trailers generally run from 30 seconds to 5 minutes with 3 to 4 minutes being most common. Besides bandwidth, your audience's attention span will influence the length.

Budget about 230 words for each minute of trailer. Select a lead sentence that will capture your audience's attention. End with a call to action that prompts your viewer to contact you or purchase something. Buttons leading to online booksellers who carry your work are a good way to translate interest in the trailer into sales.

Remember that you are fighting to hold the attention of your audience -- so make your text crisp and keep it moving. It isn't necessary to capture the entire plot of a novel. Your goal is to intrigue your audience enough to take a next step. Think of your trailer as a flirt more than a seduction.

Your script has to manage several elements: narration, images, background music, sound effects, and text animations (key phrases that emphasize a particular feature). Click here for a convenient template in Microsoft Word that allows you to break up your script into segments with sequencing for sound effects, text animation, and images.

For starters you will need a computer with a sound card that accepts line input. Check the back of your computer for a line-in connector. If you don't have one, you'll want to get an add-in audio card. The 1/8th inch microphone connector in most systems generally will not provide adequate quality for a serious microphone. If you need an add-in card, take a look at Newegg.com or zzounds.com for some examples.

Next you will need a reasonable quality microphone to get professional results. We favor a Shure Beta 58a (street price $159) run through a Behringer MIC200 tube preamp (street price $60) into the line input on our computer audio card. Note that most quality microphones require a pre-amp of some kind to achieve required line-in signal levels. Even a good quality microphone run through a poor quality built-in sound card pre-amp will produce unacceptable results.

Available equipment changes daily with new introductions and price reductions, so shop around. There are a number of Web sites such as Homerecording.com with good advice about how to get good quality sound out of your computer.

As you record your script, speak at a normal conversational pace emphasizing key words and phrases that will be illustrated with images or sounds. Record using 22KHz or higher for best results.

A basic sound editor such as Creative WaveStudio (bundled with the Creative sound card) or Goldwave ($50), will allow you to make several tries at each phrase and edit out errors.

Record several takes, have someone who doesn't know the script listen to them, and select the clearest and punchiest version.

Keep in mind your trailer canvas size. We prefer 572 pixels wide by 350 pixels high as a maximum size to avoid bandwidth problems, but images may be considerably smaller than that. Images may be scaled down in size without a loss in quality, but scaling up often produces unacceptable blurriness. A good technique for assembling needed images is to scan search results saving any images that are related to your topic in an appropriately labeled folder. Think of this phase of image search as a kind of brainstorming. Once you have gathered enough possibilities for a particular illustration, display all related images in a tool like Photoshop to eliminate the weaker choices and select the best possible candidates. Keep in mind that it is desirable to have some consistency among the images you select. Moving from cartoons to photos, grayscale to color, or low-res to hi-res may be distracting. Images may be cropped, scaled, or rotated to increase effectiveness. A single 572 x 350 pixel GIF may require as much as 180,000 bytes to download. At 56KB that will mean 30 seconds of download time. We try to keep most of our images down to 280 x 350 as a balance between impact and bandwidth demands.

Choice of font and color is important, with consistency from scene to scene as well as special fonts for highlighting key concepts being appropriate.

Remember that the effect will be synchronized with a particular image or animation sequence and should be of appropriate length. A three second sequence of dogs cannot be supported by a single half-second bark sound. Repeating a short effect is possible, but usually sounds artificial and distracting.

Search for the perfect track to set a mood at sites such as AudioSparx.com or www.RoyaltyFreeMusic.com. Expect to spend $25 to $50 for the rights to use a 4 or 5 minute track. Read the license agreement to see what restrictions apply to your use of the music.

Remember that the music track is subsidiary to the narration so volume should be trimmed in an audio editor (see Question 2 above) to a level that doesn't interfere with understanding the narrator. We frequently run the background music track on one channel while running the narration on two channels.

Flash is extremely powerful but takes a good deal of practice to make it do what you want it to. This is where TrailerMill.com staff can help the most.

The key to making effective use of trailers is to get people to see them. Google Adwords is an excellent source of Web traffic at a modest cost. TrailerMill.com can help you get focused exposure for your trailer.