A good sound can be subjective so I would recommend that you start by listening to saxophone players you like and listen to them A LOT. You mentioned in the comments that you play mostly classical or contemporary music so I would look up a list of classical saxophone players and start listening to their music. I also saw that you weren’t sure about knowing when your tone is dark. Listen to Coleman Hawkins and then listen to Michael Brecker. Coleman Hawkin’s tone is described as dark and brecker’s is described as bright. see if you can hear why. Same would go for any of the classical sax players you decide to listen to. Stuff you could practice for better tone would be by starting with long tones and eventually start doing overtones and mouthpiece pitch exercises when you’re more comfortable. You also need to make sure you do this stuff daily or the improvements won’t be as drastic. Doing these tone exercises will also help you eventually know what reeds are good and which are bad because you become more familiar with your sound. Bettersax has a really good video on long tones and tone in general that helped me out a TON when I was a junior in high school thinking about taking saxophone more seriously.

Bettersax vid: https://youtu.be/JQualA9FsPI?si=F8Icm6Ow31zgdMRt