In midst of first attempt at sourdough, by moderately skilled bread baker. Rising trouble!

Looks terrific!

Those look wonderful!
Now, I want to make some crusty bread this weekend. And make Shrimp Ajillo.
Shrimp poached in olive oil, garlic, hot peppers (or pepper flakes), smoked paprika..so it's covered in the oil...garnished with lemon juice and parsley...you use the bread for sopping up the oil. It's a Spanish Tapas dish. It's sooo good with crusty bread.

Oh how lovely! It's wonderful that you're happy with the first effort. Your barm will definitely mature with time. Within a couple of weeks you should be seeing a noticeable improvement in proofing quality and time. Another note on bread flour, be sure to only feed your barm BF. It will go after AP flour like it's Twinkies. Congratulations!

Thanks for all the detailed answers. I'll have to add some of these to my baking notes. To answer the questions: 1) It was started with flour, water & 1/4 t. Fleischmann's IDY . Hopefully, per insights from @boulangere it will get stronger over time. 2) I am in TX (105 degrees today) and used unbleached, organic a/p flour measured by weight (recipe called for a/p - I'll try bread flour next time) .

Result pic, but I haven't tasted it yet. It had that nice slightly sour, yeasty smell, so I'm optimistic.

THANKS!

Good point, Sam. I forget that recipes written for home bakers tend to indicate X cups of bread flour or AP flour, as if the two were interchangeable. With sourdough, especially, you want to be sure you're using bread flour. You're creating some pretty serious acids (acetic and lactic) and it takes the stronger protein to stand up to them. If you're not getting a good standing rise, it could be because of the lower protein content of AP flour - the acids will break it down too much.

One thing to consider when making bread. The Flour. Did you use AP flour, bread flour? What brand. Here in the south, I always have to adjust flour because the AP flour here is softer. The "Gold Medal" brand for bread flour is 135g/cup..while most USA bread flour is 127g/cup.
Here's a handy chart.
http://www.recipesource.com/misc/hints/flour-weights01.html

I failed many times making "No Kneed Bread" measuring by 'cup..after using that chart and adjust for our AP flour and using a digital scale. It works every time.

I think your pics look just fine too.

Well, first can you tell me what went into your starter? Is it a based on a commercial yeast or have you grown up your own wild yeast starter? That's one factor.

What a sourdough barm does for you in general is to grow and maintain a yeast population at a constant level suitable to then be developed into a firm dough, which adds more nutrition to your base level of yeast and lets the population develop further. When you than turn it into a final dough, and take it through its stages of proofing, the population continues to grow.

Then there's the maturity of your barm, Newborns and immature barms tend to take longer to grow a population capable of proofing bread more rapidly simply because they haven't yet reached their highest and most stable population yet. So do be patient. Chemistry and biology work, and your bread will rise. As Amanda describes, if you give it a gentle poke and it feels springy, it has some proofing to do. If it retains the indentation of your finger, it's ready for the oven. Yours looks lovely, and we'd love to see photos of your final bake.

It looks pretty good. I've found that homemade starters are sometimes slower to rise. When you press on the dough, does it bounce back? If so, it should be ready? If not, I'd give it another 30 minutes, then bake it. I wouldn't worry too much if your rising time differs from the author's -- so much of that has to do with temperature.