decsis
Your Л sounds absolutely english-like. ЛЬ is okay. (Лампа and лес) clearly confirm that.

Т (ДумаеТ) sounds perfect, ТЬ in думать sounds like an English T. Bend the tongue more or just spread sides of the front part of the tongue from the ЛЬ position, widen them to stop the airflow completely pump up the air into your mouth and you will get the Т when abruptly release the pressure.

Достопримечательность:
СТ transition not sharp enough, the T should bounce off the top of the mouth after a short complete deadstop, not just make a noising (English TH-like) sound.
И sounds English like e.g. like EE in sleeve.
ЧА both sound English-like, and if you saw that lesson you should have read that Ч is always soft and no hard vowels like A after Ч. Only Я. Read it as Я.
ЛЬ almost not existing. Make sure you are pronouncing it. Exaggerate it a bit. Make that click to force the ЛЬ sound.

Demonic_duck
Думает has wrong stresses there, just the А is too clear as though it would have been stressed too.
Достопримечательность - the T is not sharp enough. Make sure it quickly stopped the airflow. And Ч is a bit English-like.
And yes, you're almost right about this Y in yacht, except It should be more like Russian И than English Y. And they use different tongue positions.
I think the И sound is a key or is a glue to understand and learn how to pronounce Russian soft sounds correct.