What a great opportunity to learn and grow!
The only problem I had with my photos in general was the flash glaring in some of them. How should I use a reflector to take care of that, and what color reflector should I use? Also, should I get an external flash in place of my camera flash to supplement the single softbox I have, or should I buy a second softbox? Does anyone have any advice?
Yes, lighting is one of the main issues I was noticing in these photos. Direction of light and quality of light are both very important in these types of photos. If you notice, the lighting here is mostly front lighting and harsh (you can see how hard the edges of the shadows are).
The reason people use multiple softboxes in a lighting setup is both to control direction of light (i.e. set up on both sides of the subject), as well as the harshness, or quality, of the light.
The benefit of a speedlight rather than the built-in camera flash is that you can angle the light where you want it to be, and you can also diffuse it by bouncing it off something like a white ceiling.
Personally, I’d recommend learning a bit more about lighting before investing too much in it, so you know a bit more what would be good to invest in! You can use natural light for free by taking photos near a window or outside. 🙂 And that’s a good way to learn about lighting. Observe things like color casts, soft vs hard shadows, angle of light, color of light, etc.
Lighting is an area I’m definitely learning and growing in as well! 🙂
There are a few resources here on Lenspiration that might be helpful to you in studying this area: Lighting for Still Life Photography, How to Use Bounce Flash, and a post on 12 Tips for Puppy Photography.
Hope that helps!