1. based on the setup, I'd venture to say your bike's too small for you. Try for a fit more like this:



2. I find clipless pedals improve efficiency over clips & straps.

3. If conditions permit, try this hand position when you're up to an airspeed where air drag begins to dominate:



At 20mph this is worth over 1mph for free. It channels air around your body instead of scooping it in like a wide hand position does. You may not see as much benefit if your bike's forcing you to sit upright. A bike with more top-tube length will let you stretch out and use your back muscles (how many racing rowers do you see who pull on the oars while sitting bolt-upright?).

4. You can get higher road gears with a new crankset that has larger rings, something with a 48-tooth ring would be good. If you need to stay economical, Shimano has Tourney models with non-replacable chainrings. I use my 48 x 11 every day on my mountain-commuter when winding up for the dash across the bridge.