Haven't read everything, so this may have been said already:
1) If you configure two/more devices inside one single segment (same network address), you don't need any default gateway. The default gateway is the way all packets to 'elsewhere' go. (The network address is the local IP binary ANDed with the network mask, e.g. 255.255.255.0 says: "First three octets/bytes are the network part, the last one is the host (specific) part".)
2) Make sure your layer 1 connects: the connect LED has to light (and go off when removing the cable) and the traffic light has to flash while transmitting to and fro (ping).
3) If you use a simple crossover cable, the n-way negotiation may not work. Manually set speed and full/half duplex to matching values on both sides. You might better get a small hub/switch to take care of that.
4) If ping works, try it with larger packet sizes; when smaller packets work but larger ones don't, it's usually a duplex mismatch.