I've never personally done it, but have read and watched a lot on the subject, there are a lot of resources on the subject. I know Thermal Grizzly - Conductonaut is very popular.
As I said this will certainly void your warranty, and if your OK with this you could first try and apply a higher quality normal thermal paste such as Thermal Grizzly Kryonaut or Arctic MX-4 underneath the heatsink. I should also state if you do go down the liquid metal route, be very careful and watch and read everything you can about it. Also if you have a Aluminum heat sink then you're out of luck as Liquid Metal and Aluminum don't mix.
You'll also have to find a video or other resource on opening up your laptop and getting to the CPU to do either. You could also do the GPU while your in there.