To acquire properties in Texas for back taxes, you first need to make sure they are going up for auction. You can check the Tax Assessor Collector for this list. Once you have identified a property, do a thorough search on the property. Though when you purchase the property for back taxes, in Texas if it is a homestead property the owner has a right of up to 2 years to get back his property. 6 months if it is not homestead. He would have to pay you back what you paid plus 25% penalty if paid in the first year or 50% if paid in the second year (homestead only). Look up
www.foreclosurehouston.com for more info. I don't know what city in Texas you are in but this website should get you started. Good luck.