Keep this in mind,
As you live in this day.
*I didn't like how you said that. I would maybe say "as you live each day" or something like that.*

Take the hints from those signs,
And follow the correct, not wrong way.
*This last line seems kinda forced. I would change it to "and live your life the correct way" something like that, so you can keep the rhyme but it also makes more sense*

On one day,
You will be happy,
Feeling the warm sun's rays.
And the next you won't be able to see.
*I liked what you were saying here but you lost me at the last line. I would maybe explain that part better*

And to nothing you should ever cling.
*This sounded like another forced line. I'm not sure how to fix it though*

When time's up,
*I would say "when the time is up" that sounds more appealing then the way you wrote it.*

Will be connected to wrong ties,
*Did you mean to say "We'll be connected to wrong ties?*

And our life will one day be snuffed.
*I loved how you used the word "snuffed" here. Very clever*

Away from anything that is not true.
*"untrue" sounds better and less wordy than "not true"*

This is the end,
For the time's gone.
I hope that you will win,
As through life you have undergone.
*I liked how you ended this. It's almost like an instruction manual to living a good life or something. I thought that was very creative. There was some parts that bothered me a little but other than that I think you did a good job with this. Keep it up hun. Nik*