Perhaps, remove the boot animation completely. Check necessary hardware (i.e. USB devices etc. take longer to initialize). Startup programs / services. If booting into logon screen / desktop -in case you have no password,- in the fastest time possible, look into delaying services. Some you don't want to. But anti-virus etc. stuff you can try to delay load them.
At some point, it's just the initialization of different hardware that's going to take time. For example, I have a USB TV Tuner. Boot process does pause couple seconds to get this fired up. So, look into hardware. The minimum you have the faster it'll boot.