Here is a method I like using when finalising my logos and looking at how a logo would look in various colours. With all my designs I first create them in black and white. This is so I can see that my logo is at a high quality even without the colour. I believe if your logos need colour to make it better then your design is right yet.
Many graphic designers feel colour is the answer to everything yet I see it as only an enhancement to the design. An enhancement as is in it is not needed to make the design any better. Colour is used for the branding and theme colorates to the brand itself . For example, if the brand was about living a healthy liefstyle I would use colours related to nature such as green, and blue. Colours are powerful and helps the viewer get a feel of what the brand is about.
