1st time In San Antonio

Riverwalk and Alamo region is the top Tourist destination in Texas.
Alamo you need to take a ticket at the info desk (it's free) to get a time that you're allowed in...most people grab a ticket and go right in.
Riverwalk is definitely unique and the Boat Tours allow you to Bring Alcohol on board. They're short (about 30 minutes) and informative. You'll find the oldest Bar in San Antonio called the Equire Tavern, it also has the longest continuous Wooden Bar in San Antonio. Schilo's is the oldest restaurant in San Antonio. Go for the Root Beer there.
The Pearl region is the new place to go for a City Centre type of experience.

Top Tier value for Dining out and being gluttonous is at Umiya Sushi near Medical Center. Their Dinner All You Can Order is $30, is available outside of Dinner hours, and offers a massive selection of rolls, Sushi/Sashimi (Yellowtail and Octopus are the stars), Hibachi Shrimp and Steak, and the appetizer triumvirate of Tuna Tataki, Yellowtail on Fire, and Salmon Tataki.
Visit Bunz for massive, messy burgers worthy of a photograph and the entire paper towel roll at the table. Visit Mr Juicy for a flavor-packed Burger that fully satisfies.
Saturday and Sunday are for Barbacoa with Original Donut Shop offering a winner in their Barbacoa Taco (Flour tortilla), add an Egg to prevent the Barbacoa oil run-off while turning it into Breakfast. Rios Barbacoa is the place to go (especially with so many locations) for 1 pound to go and free donuts & coffee.
Berni Vietnamese for their photographic Back Rib Pho or complex and layered flavors of Flaming Steak Pho is exceptional no matter the weather.
Taquitos West Avenue provides reliably good tacos any time and Thursday through Sunday include Al Pastor with weekend hours stretching into 3AM.
Visit Artea for their rich Bonsai Milk Tea and Taiwanese style Popcorn Chicken for a savory afternoon tea.
Best Quality Daughter offers a winning menu with almost any dish. The execution leaves little to be desired and the portions will not disappoint.
Cured offers the "best" happy hour in town and even does so on the weekends with a small selection of local beers, at least 1 house wine, and at least 2 house cocktails (usually one is a Sangria) with an entire list of small plates available.

Howl At The Moon is absolutely The Place to go whenever there's a craving for live music, lively atmosphere, and happy energy. As a bonus, they have a taco stand downstairs and an upscale lounge also downstairs.
1902 is a consistently high energy, primarily EDM influenced audience and sound. Look for plenty of tables with plenty of sparklers for their bottles.
The Moon's Daughter is the most relaxed of the major Rooftop bars. Expect a quieter time with a focus on the table flames and the open air surroundings.
The Blind Tiger provides a Speakeasy feel to what is essentially a basement for Comedy shows.