Evaluating Demographics Online

[Forrest Holt]

I'm attempting to narrow my criteria for multifamily properties here in Houston and having trouble filtering through websites for demographic information. I've attempted a few different google searches but I can't tell if these sources are credible. I'm honestly a bit overwhelmed and uncertain of what information I should focus on. Can anyone assist with a credible source online/offline? What demographic information should I focus my attention? 

[Satha Palani]

I look at citydata.com. Search by zip. The site shows data by zip broken down by block code / census area. Number of different metrics. I typically looks at median household income; both recent data and % change from last census