can I improve my child's speach sound use at home if I am told which sounds she spoke in error?

by Andrea
(Seattle)

Speech pathology students came to my daughter's preschool. She is 4.5 years old. They circled "t", "k", "g" and "sh" as sounds she made were in error. Also they indicated they did not hear her use "st" blends. Can I improve my child's speech sound use at home if I am told which sounds she spoke in error? Are there exercises I can do? She was not in error for other 5th 6th and 7th year benchmarks. She does not have a hearing problem. I have been told she doesn't demonstrate other behaviors or produce other errors. Is it important to send her to a speech therapist prior to regular assessment in kindergarten if she is not showing any other delays, or social or learning challenges due to her sound errors currently? I would like to pursue this at home. I was not in the habit of correcting her sounds as she as seemed to self correct and I didn't want to make her self conscious in a detrimental way ( she has always seemed to self correct over time). Now that I am aware there is a need I am happy to gently intervene as needed. Thank you for any guidance as to how important pre kindergarten intervention is on minor sound errors.