I second the suggestion  Pearl Brewery for the best restaurants in town. We tried 3 great ones there:  Il Sogno (delicious Italian, don't forget to make a reservation),  La Gloria Mexican Restaurant (mexican street food, small portions - cheap! - to try several different things) and  Sandbar (seafood). The one restaurant I like at the  Riverwalk is  Boudro's On The Riverwalk, most restaurants at the Riverwalk are tourist traps. Boudro's is the one we keep going back to (we live in Austin and go to San Antonio a few times a year). Acenar at the Riverwalk was a new discovery, it's a good mexican place.  Luke at the Embassy Suites lobby and facing Houston Street is a good bistro, they had a jazz brunch that I wanted to try but we went there for dinner.  Rosario's Mexican Cafe Y Cantina is considered the best mexican in town, but we haven't been there yet. 

There is great fishing  Port Aransas or  Corpus Christi--easy day trip from  San Antonio.   Downtown San Antonio has great restaurants but the best Mexican is usually the dive at the corner.  Tons of shopping--some of the better locations are at " The Rim Shopping Center" and The Shops at La Cantera--both are NW part of SA. Have Fun!!!

Great time of year to be coming to SA. Great choice of restaurants at the restored Pearl Brewery complex. Also, good restaurants in Southtown ( Bliss,  Feast, etc). Shopping is best at The Shops at La Cantera La Cantera mall or smaller boutiques in Alamo Heights Alamo Heights. As for fishing, Port Aransas Port Aransas is closest for Gulf charters. Enjoy!!

We lived there for 7 years and loved it! La Fogata is a favorite and also anywhere down on the Riverwalk. Great atmosphere and beautiful surroundings abound. Also Mi Tierra Cafe & Bakery corporate office is a classic. Corpus Christi is probably the best place to look for fishing. Have a great trip!

I'll start with the fishing question first: 2 hour drive to Corpus Christi and book in advance with Captain Allen of Fish On Pro http://www.fishonpro.com He's the best guide! Tell him I recommended him. We always catch fish when we go  out with him.

Food you must try are the puffy tacos Los Barrios Mexican Continental Cuisine They were in a "throw down" with Bobby Flay, so my husband I had to try their food. Delicious! Casual attire, btw.

There's a Mercado that's fun around the river walk for shopping. Also, check out the beautiful gardens Japanese Tea Gardens There's also great shopping in Gruene gruenetexas.com/Maps/map-shops.php (40 minute drive) It's a must to check out Gruene Hall if you go. Many famous performers started playing there.

Have fun! 

Corpus Christi is the easiest to get to for fishing, interstate from San Antonio and plenty of options for hotels, food and fishing outfitters from Corpus.

San Antonio-if staying on the river walk, avoid the large restaurants or chains-try Acenar for the best Mexican on the river. Boudro's is a great all-round.    awesome restaurant. A bit higher end = Biga On The Banks or Bliss which is just a bit off the river but if the weather is comfortable, the fire pits on the patio are awesome. Say hi to the chef-Dorian for me if you go.  Breakfast at The Guenther House is a must with a great gift shop in a national historic registry house.  

Too many good places to eat to mention, but if this is your first visit try Casa Rio and County Line Barbeque of San Antonio on the Riverwalk.  The nearest place for salt water fishing charters would be out of Rockport (Texas), Port Aransas or Corpus Christi. If you can find an extra day or two in your schedule, we make South Padre Island our go-to vacation spot to get away from it all. Great fishing, dining and wonderful atmosphere. (Reminds me of OLD Miami). 

Down at the gulf you could check out Rockport (Texas) or Port Aransas. Mustang Island at Port Aransas is a nice area for doing fishing and there should be plenty of charters from that area. In San Antonio, if you want to do some shopping, you'll want to check out The Shops at La Cantera, a great outdoor mall with lots of interesting stores. Also, across I-10 from La Cantera, is The Rim Shopping Center, a huge shopping center with big movie theater, a Bass Pro, JC Penney, many other stores and probably half a dozen great restaurants (including Maggiano's, BJ's, Red Robin, Mimi's Cafe, TGI Friday's, Stonewerks, just to name a few of the great options). This area is located at 1604 and I-10, but if you are downtown for your convention, there are much closer shopping and dining options. Start with the Riverwalk and the mall there. There are dozens of dining options along the Riverwalk, so you'll be able to take your pick based on what you're hungry for at that time. 

Head to the Galveston area

Visit the missions at San Antonio Missions National Historic Park

Eat at Q on the Riverwalk