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In terms of general advice compostion advice, before taking a shot consider what story you want it to tell the viewer, what it's "punchline" focal point is, and what if any context is needed to understand the story. Finally, if the intended audience are strangers why would they find it interesting?
Asking yourself and thinking about those questions will help make composition decisions such as where in the frame to put the focal point, how tight to crop to show the surrounding context, and sequence viewers are likely to process the content.
If the viewer scans over and sees the context of the background first, then finds the focal point it creates a different storyline. If the foreground/background context is seen first the viewer will understand the complete story when they find the focal point. If the focal point jumps out and grabs attention first, then the wander off it to explore the rest of the frame content the "Ah Ha!" moment where all the pieces of the puzzle fit is delayed.
Techniques like blurring the background with DOF or motion work to isolate the focal point from the background so all attention stays on it. The viewer finds it and doesn't wander off it and forget it. It's the technique to use when there's no additional context / information needed to understand the story.
With that general advice in mind consider your three shots:
1) Indentical flower heads in backlight: There's an interesting diagonal connecting the sun in the upper right with the "bullseye" flare circle in the lower left. The main group of flower heads is in the middle of that linear 'ping-pong' eye path. What is a distraction from that dymanic are the two flower heads in the lower right. In a situation like that what I'd do to get rid of that distraction would be to just fold the distracting heads down out of the way.
2) V/W: This might have been a grab shot, but the fact you were located where you where shooting into the shadow side of the V/W makes the lighting and 3D modeling far more interesting than if you were on the other side with the sun at your back. There's a lesson there you might not consciously recognize but also incorporated in the first shot: 3D modeling of most things other than faces is more realistic in 2D photos when you face towards the dominant "key" light vector and shoot into the shadow side.
In terms of 'story' here it's simple: look at the neat old V/W. I'm old enough to have ridden in them when they were new, so it triggered a smile . Your split-second composition decision to leave space in front was a good one. It's also the type of situation where blurring the background works to isolate the focal point because the context of the location really isn't important. One of the reasons the composition works well is because there aren't any other cars, people, buildings distracting attention off the focal point. In your case the the fact the your car was traveling in the opposite direction created the blur and was a 'happy accident'. For future reference you can blur the background as streaks with a technique called 'panning'. Set the camera in Tv (manual shutter control) at a low speed like 1/30th and pan the camera with the car as it passes. It takes a bit of practice to master it.
3) Bike: This is the type of shot where there's a focal point (bike) and background context which explains where and why it is there. It would be a more interesting story if you had backed up a bit and shown more of the focal point bike and the background. Move around left / right, higher / lower and watch for distractions like that brown pole in the background. Further back, more to the right and higher or lower angle would have been more interesting. Decisons like that are easier to make by comparison when editing so when shooting err on the side of shooting wide vs. getting the crop 'perfect' in the camera and also shoot from as many different points of view as possible.
If you can find something to stand on in a situation like that to get the camera looking down it will rotate the distracting sky and houses out of view and surround the bikes with pavement to isolate them. That would have worked here because the sky and buliding context in the shot really don't add much to the story. Like the U/W shot the story is simple here: look at the neat bike. It's disappointing not to see more of it. Like I said at the begining think about what your focal point is and how best to show it then frame the rest of the story around it. Also get past 'tunnel vision' on the focal point so you can spot distractions in the background, like that pole.
If you had moved more around to the right in front of the bike to shoot that pole would have been in front of the bike. In situations like that I'll compose to a pole or tree is on the very edge of the frame acting like a frame for the action. Here's an example of what I'm describing:
As for the exposure? Chrome reflect the light source and will usually clip and lack detail when a solid white object next to it is correctly exposed. So you actually did a very good job exposing it.
The camera sensor can't handle the contrast of a sunny day, which explains why the background is over-exposed. But since the background context isn't important that works in a good way to help isolate the correctly exposed bikes in the foreground. When you choose to correctly expose the focal point and not the background it tells the viewer of the photo subliminally 'don't bother to look here, it's not important' in the same way blurring a background does.
Overall you've got a very good eye for finding interesting content and composing it efectively. Hopefully my general advice and analysis of the photos will help you hone that vision so you can spot the good one on your own during shooting and when editing.
You don't need to wait for a 'good camera' to take photos. Use your phone. You may not have the same degree of technical control but you can hone your storytelling and composition skills. I've got a tutorial site that covers much of the same ground in more detail at http://photo.nova.org/ you may find helpful.