Texas scratch-off games are generally created equal. Typically there are 50-75 cents in prizes for each dollars worth of tickets. However over time this changes. For any given game prizes may be claimed early in the sales cycle and the payout per dollar starts to drop. But when prizes are not claimed and tickets are being sold the ratio for that game starts to go up.
Your chances are better when buying a ticket for a game where the ratio of prizes to remaining tickets is high. The higher the better. But you want to shy away from those games where the ratio is low.
Lottery Smart Texas takes the most current lottery ticket information and ranks Texas scratch-off tickets based on these ratios, assigning each game a "Power Rating". The higher the Power Rating the better your chances of winning.