1. Its way too long. Get it under 90 seconds (including your titles, which TBH could be a slate with your info, unless you you want show off some animation skills. This would only be worth it if you did something complex, but fast)
2. speed up the beginning sequence, I was bored after two shots (I kept watching, but your clients/potential employers won't)
3. A good chunk of your shots were out of focus, some seemed to be artistic (shot of the dog in the grass with the sun coming towards the camera) but many seemed like shots you liked, but they weren't perfect. I'd say cut any shot that presents a mistake in your filming, that leaves people unsure.
4. You had way too many shots panning up into the sky, repetitive shots get boring, keep the best ones, cut the rest.
That's about all I got for now, basically 2-4 will probably fulfill #1. Natural sound is always great, but you have a large variety of clips. Ideally when you shoot now, always think about getting some shots just for sound, sometimes I'll set up a shot and shoot it, then again from another less attractive angle, but closer to get better audio. Or if you have another camera, you can set up a closer angle, out of your angle, to grab audio, tons of ways but its easier to capture that sound when you're already out there vs going out again to get just audio clips. Good luck man