Milton,
There is no single best practice for ECC ATP. Each company has different business requirements, and these requirements translate into different ECC solutions.
If your main requirement is to perform a FGs Sales order availability check, based upon the availability of components for a single-level Bill of Materials, then there is a standard solution using Strategy 82. You and I visited this topic in 2011. http://scn.sap.com/message/10078850#10078850
In general, you can find baseline Best Practices docs at http://help.sap.com/saap/sap_bp/BP_BL_ERP607_USV2/HTML/Content_Library_BL_EN_US.htm
and these docs will contain a bit of ATP stuff. If you have a specific industry in mind, check the industry specific BPs at http://help.sap.com/bp-industrypackages ; some of which contain ATP solutions.
Best Regards,
DB49