How can you make stories more exciting and tense?

Look at this example of a student’s work:

I’m not going anywhere,” I said to myself.
I went to the back of the car strangely greeted by dozens of books on the floor, – the title read “Return to Sender”. Slowly, I turned back to the road I’d just driven down.
What grade is it and why? If the rest of the story continued in this level of detail it would be somewhere around a grade C, though not a great one as it lacks descriptive detail. There’s no clear mood or sense that the writer is trying to build up tension. it uses I a lot, which in such a short space, feels repetitive.
What’s good about it?
It’s clear. It’s well punctuated and there is some sense of mystery.

How to Improve:
+ Vary the start of sentences

+ Use more interesting verbs (see below).
+ Structure sentences so that the important information comes at the end. This will build tension (see below).
+ Add adjectives and sensory language to build mood.

Improved Version

Scattered across the road was something white, like linen flung across the tarmac. [this builds suspense because you don’t find out what it is until the very end of the sentence, and even then, it only looks like laundry] Moving closer, my blood froze. [I’ve shown you he’s afraid. But I haven’t told you why…] Dotted, not-quite-randomly across the hard black tarmac were about ten books. There were more in the now open trunk of my car.

But I hadn’t put them there. And they were all the same edition of the novel I wrote last year, ‘Return to Sender’.

Example Two The bridge groaned at every step placed on it. Fearfully, I edged further across. The target was on a wooden board stretching the width of the bridge which was strewn with plywood and old tyres, slick with the recent rain.

The further out I went, the louder it creaked, sending a shiver up my spine. I bent down. It looked like such a small thing, the brushed aluminium surface catching the light from the lonely lamp below. 

As my hand reached down to pick it up, I almost dropped it from the heat. Finally, I got a grip. It sounded like it was half full by the weight, of some hot liquid. Jumping the last few metres, I returned back to tarmac where it was safe. It felt like an achievement. Attached to the object was a piece of notebook paper which was pure white and the cramped handwriting looked similar to mine. It read…

Student’s Work
The top of the mountains were getting close and the fog was approaching. I climbed. Wild fog drifted before me. The top I reached but the fog had beaten me. I now had to make by shelter within the cold damp. Trees were nowhere in sight and the wild goats had dropped to the lower mountains. I was homeless, hungry and dehydrated. To hide from the weather I thought of going back down to where the goats had retreated, but no strength was in me any more. I lay there in my damp, cold and torn clothes, till someone would find me dead or alive.

This is a big improvement on the piece above and would score a solid B.

How to Improve?

Develop this with more detail about trees and foliage underfoot and slimy and jagged rocks. Also, the sentences still need to be varied.