To connect your laptop to RP directly using an Ethernet cable do this:
On your laptop:
sudo ip ad add 10.0.0.10/24 dev eth0
On your RP:
sudo ip ad add 10.0.0.20/24 dev eth0
Test connection to RP from your laptop:
These instructions are from here
If you want your RP to receive IP address automatically you have to connect it a device that has a DHCP server running.