This is my 2nd attempt at cultivating a Tamukeyama maple. Both my first attempt and now this one has started to exhibit browning leaves at the very tips. I planted this one back in mid-spring.. It started very small, but has gotten bigger over the summer.

I'm in Dallas, and this summer wasn't overly hot. Watering occurred twice a week and it has direct and filtered sun exposure for several hours in the early-mid day and full shade in the afternoon.

I could really use any tips or guidance! Thanks in advance!

I was at the nursery today and your picture looked like all of their trees. I hope some of the experts weigh in.
I'm hoping to get one next year.

This time of year, all JMs look bad, their leaves are fragile and every little ding shows. But twice a week water in Dallas doesn't seem like enough. Make sure the soil stays damp. Mine are watered daily in summer. The soil needs to be damp in winter too so if it doesn't rain, remember to water.

Thanks for the watering tip, Daisyl! I'll definitely up the watering to maintain a damp soil level!

So moist soil all winter (and all year) long is advised?

Yes, especially if you live in a cold area.