A good strategy guide for a game should include the following.
1) Basic deck building guide lines to get players started. Nothing too fancy or in depth. just to get the player's feet wet when it comes to the game.
2)Highlight the different factions/colors, giving a bit how they play and what they are about. Use this as a way to explain more advanced tips and tricks one at a time.
3)Links to resources such as rules erratas, advanced rulings, or even deck lists. While a faq in the guide is a good idea, you don't want to bog down the guide into something too long and convoluted that would cause a new player not to read it. Give them the basics, then give them the tools for them to expand their knowledge should they want or need it.
Out of curiosity, what game where you thinking about doing a guide for?