Hello. I recently purchased a 15 year old bonsai. I'm really excited about it and love the tree but I think there's many aspects to it where I don't think it is growing like a natural tree would. I've had the tree for a few months now and have done some minor trimming but any advice on trimming and tools would be very much appreciated.

Welcome, Paul.
I don't think this Ficus is 15 years old, at least here, to be 15 it would be much bigger.
But it is a nice tree.
You could take some dead weed from the soil, wire it to better position the branches,
As for the tools, you are going to need a very sharp pair of bonsai shears, a branch cutter, chopsticks, wires and a wire cutter.
See:
www.bonsaiempire.com/forum/tools/10748-show-me-your-tools

Thanks Clicio! Very helpful and insightful and beautiful tree in your picture by the way.

I wasn't sure if it was too old for wiring but now I definitely will. In the photos there's a few things I point out, in your opinion would you cut them or wire them to a new position? Also, do you have any suggestions to encourage new growth to make the end of a branch fuller? I purchased a bonsai book and watched some youtube videos. Both were helpful but I'm still nervous that I'll make the wrong cuts and lessen the beauty of the tree. I bought trimming tools on Amazon that are very sharp and work great for trimming new sprigs. I didn't think they would work on undesirable branches. I'm going to pick up a branch cutter, wire, and wire-cutters at the local hardware store based on your suggestion. Do you use the chopsticks to help with the wiring? Thanks again!

Also, some of the sprigs are really long before a leaf occurs. I believe I need to make my cuts only above leafs or the sprig will just die. Is this correct?