diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..046c4b1
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,15 @@
+Contributing to Turnpike
+===
+
+Pull requests and bug reports are appreciated.
+
+Pull Requests
+---
+
+1. If you want to contribute a major feature or change, please open an issue to
+   discuss first.
+2. Please run `go fmt` on your code
+3. Check that `go tool vet ./` produces no warnings when run from the directory
+   where you made changes.
+4. Write a test for any non-trivial changes.
+5. Make sure all the tests pass.
diff --git a/router_test.go b/router_test.go
index f4948b1..86fe047 100644
--- a/router_test.go
+++ b/router_test.go
@@ -34,7 +34,7 @@ func basicConnect(t *testing.T, client *basicPeer, server Peer) Router {
 	}
 
 	if len(client.incoming) != 1 {
-		t.Fatal("Expected 1 message in the handshake, received %d", len(client.incoming))
+		t.Fatalf("Expected 1 message in the handshake, received %d", len(client.incoming))
 	}
 
 	if msg := <-client.incoming; msg.MessageType() != WELCOME {
diff --git a/serialize_test.go b/serialize_test.go
index 24fa57f..fdeab9d 100644
--- a/serialize_test.go
+++ b/serialize_test.go
@@ -30,9 +30,9 @@ func TestJSONDeserialize(t *testing.T) {
 	s := new(JSONSerializer)
 	for _, tst := range tests {
 		if msg, err := s.Deserialize([]byte(tst.packet)); err != nil {
-			t.Error("Error parsing good packet: %s, %s", err, tst.packet)
+			t.Errorf("Error parsing good packet: %s, %s", err, tst.packet)
 		} else if msg.MessageType() != tst.exp.MessageType() {
-			t.Error("Incorrect message type: %d != %d", msg.MessageType(), tst.exp.MessageType())
+			t.Errorf("Incorrect message type: %d != %d", msg.MessageType(), tst.exp.MessageType())
 		} else if !reflect.DeepEqual(msg, tst.exp) {
 			t.Errorf("%+v != %+v", msg, tst.exp)
 		}
@@ -79,7 +79,7 @@ func TestBinaryData(t *testing.T) {
 	var b BinaryData
 	err = json.Unmarshal(arr, &b)
 	if err != nil {
-		t.Errorf("Error unmarshalling marshalled BinaryData:", err)
+		t.Errorf("Error unmarshalling marshalled BinaryData: %v", err)
 	} else if !bytes.Equal([]byte(b), from) {
 		t.Errorf("%s != %s", string(b), string(from))
 	}
diff --git a/websocket.go b/websocket.go
index f51e046..cb82cae 100644
--- a/websocket.go
+++ b/websocket.go
@@ -27,7 +27,7 @@ func NewWebsocketPeer(serialization Serialization, url, origin string) (Peer, er
 			new(MessagePackSerializer), websocket.BinaryMessage,
 		)
 	default:
-		return nil, fmt.Errorf("Unsupported serialization: %s", serialization)
+		return nil, fmt.Errorf("Unsupported serialization: %v", serialization)
 	}
 }