Andy,
Without more to go on it is hard to make a long distance diagnosis, sometimes I can't tell what is going on with my plants when they are right in front of me.

The more you can tell us, species is indeed one of the most relevant, the more we can help.
The yellowing leaves can indeed be an indication of watering too frequently try using the chopstick method to determine when to water. Notice I said when not how much. Look [url=https://www.helpfulgardener.com/forum/viewtopic.php?t=1479]here[/url] for basic tips, including watering.
Norm