Spend time watching and working with other, more experienced, coaches at your gym. Have they had you work alongside or spend time shadowing another coach? I imagine you teach your current classes with someone else? Spend time watching and learning from them, ask them questions if you are unsure or just curious about something. Every coach is a little different, so you don't need to adapt every part of your coaching style to your mentor, but it's a great place to get started. See if there are opportunities to just watch other classes. Does your gym provide periodic training for coaches to teach spotting? If not, ask a coach to help teach you. And if you ever don't know how to spot something, ask! Just take in everything that you can!
And blogs and YouTube videos are great resources as well.