The easiest way would be to store everything you can on the stack. The Go compiler does a very good job at escape analysis and tries to put everything on the stack that does not escape. Therefore, it's often better to use output parameters instead of return values to reduce (or eliminate) the number of allocations.
Some careful thoughts about the memory layout of your structs, especially which of them should be embedded and / or passed around by pointers and which of them shouldn't, might also pay off.
Another common optimization is to put the allocated objects back to a memory pool for later use. Take a look at the bufCache channel [1] from the bufio package for example (the http and the json package are using the same trick).
Some careful thoughts about the memory layout of your structs, especially which of them should be embedded and / or passed around by pointers and which of them shouldn't, might also pay off.
Another common optimization is to put the allocated objects back to a memory pool for later use. Take a look at the bufCache channel [1] from the bufio package for example (the http and the json package are using the same trick).
[1]: http://tip.golang.org/src/pkg/bufio/bufio.go#L79