How To Use Most Ham Radio Handhelds

I bought a Yaesu FT60-R and everything is stock. Any recommendations on what the best antenna upgrade would be and also, can I change to a lithium ion battery?

@nprgsclsgn I prefer Diamond antennas https://www.diamondantenna.net/Product_Catalog/HT.html . As far as the battery, I'm not sure. I do know I need a higher capacity battery for my FT-70D.