I presume you do not actually mean editing the raw vector data but editing the cartographic representation of that data.
The simple approach to representing lines that share the same location would be to change their symbology from the default Simple Line Symbol to Cartographic Line Symbol and then set an offset as required. You can then save this as a Layer file and so use the same symbology with other files.
You say you are a novice so here's a quick "how to":
Let's say you have all your lines in one feature class. Double-click on the feature class in your table of contents. You will get the Layer Properties dialog. Select 'Symbology' tab. Click on 'Categories' in the 'Show' menu on the left. I guess you want 'Unique values'. Choose the value you want to use for your representation in the 'Value Field' and then click 'Add All Values' button at the bottom. Now double-click on one of your lines and another dialog pops up. Click 'Edit Symbol'. In the Properties section, click on the drop-down box marked 'Type' and change it to 'Cartographic Line Symbol'. Next select 'Line Properties' tab and set your offset. Rinse and repeat. Then save all your hard work as a Layer file.
Alternatively, if you are going to use this a lot, you might want to set up a style. Go to Customize->Style Manager. Choose 'Line Symbols' from your styles list (you may have to expand the list using the little plus next to it). In the empty right-hand pane, right-click and select 'new'. Then follow the procedure above to create you style. You can use this style by selecting 'Match to symbols in a style' in the layer properties dialog.