My family is going to rent a house on the Rockport Canals near salt lake for vacation and i was wanting to see if there was anyone there or who has been there that could give me some tips on fishing the canals or the bay over there.

will you have a boat? if so, get a hot spot map and try some of those locations. the bayside shoreline of San Jose Island is usually productive. pay close attention to the depths on the map. also the no motor zones around redfish bay.

For a lot of saltwater fishing you can get by with a good topwater bait and circle hook jigheads using fresh shrimp.

If you are going to be locked into fishing the canals here's a couple tips.

Small soft plastics that look like shad on a 1/8th oz jig head and also gulp shrimp. This will work better at night in the lights of the canal, but can work in the daytime as well. And yes, like above, a small walk the dog topwater like a spook junior in any minnow, chrome, or pearl ish color will draw strikes as well.
Fish around pods of shad moving through the canals if you can spot them.. small surface ripples give them away. Also fish the edge of the canal like it's structure, and same goes with docks.

Redfish will be more on the edges and under the docks... but you have to work the bottom.. you will get hung up fishing for them, but that's just part of it. The other option for redfish and drum is using cut mullet (or any cut baitfish or even frozen shad). Use one of your rigs and rig it up with an egg weight with a swivel and an 18" leader of 20lb mono or fluorocarbon leader, and a circle hook. I think a size 3 should be about right for a slot red or drum. Use any of the cut bait above, cutting it into ~1.5 inch - ish pieces. You can also put live of dead shrimp on the hook as well. The dead bait will result in more catfish and non game species but that's part of using dead bait.

Talk your buds into going with a guide for a morning while you're down... split between 4 guys it's worth it.
ya'll have fun.