- All assumptions go to a single sheet, to change this is a cardinal sin. There should be no hanging numbers (yes not even tax rates or some other arbitrary number) in any sheet. If I gave the assumption sheet to a someone who knows what he is doing, he will be able to recreate the entire model from the assumption sheet.
- All inputs (hard coded numbers) are colored blue (typical conventions) and only those generally need to be changed. To avoid complexity you can just use one color code, but lot of modeling people i know use a master sheet in which they define what each color coding (assigning a color to a particular text or no).
- The units of each input need to be clearly defined and so should the dates.
- Use links and formulas, there should be no repetition of the assumption numbers anywhere (this is damn irritating, you are trying to see the change in the model based on one assumption and you find that you have to change the inputs at a zillion places)
- Coloring cells: This is a bit of an open area, I personally dislike a lot of colors in my model, but lot of modeling gurus prefer using them (as i said, I am a dummy)
- Do not hide rows, columns (or sheets for that matter). If you don't want the focus there, just group the rows/columns. The viewer will decide whether he wants to see them or not.
Please save continuously, Jesus saves.