PCB design for MAX1709ESE
Most of the heat will come out of the leads, so you should try to have large areas of copper connected to the pins that are common with each other in particular. 

Even though you don't have the EP package, look at the MAX1709EVKIT layout. 



Try to have 0.5 to 1 inch² (total) copper areas connected directly to the pins, and pours on both sides of the PCB will help spread the heat.