The best way to get autographs is to go very early and catch the team where they exit the cabs to enter the stadium. Some venues are better than others. It's hit and miss as well. I've gotten as many as 19 in one day and as few as 2-3. Some stadiums, like the Ballpark in Arlington, have a limited access drop off point which stifles all chances. If that fails, just try during BP...but you'll be lucky to get more than two and probably won't get the big names.