One thing you can do to get started would be to record yourself and post the link as a discussion — you’re certain to receive a lot of free help from the community.
You may want to use “The North Wind and the Sun” — it’s familiar to many people and phonologists are used to using it, so we can spend less time guessing at what you’re saying, and more time analyzing the pronunciation.
Text (version from Wikipedia):
The North Wind and the Sun were disputing which was the stronger, when a traveler came along wrapped in a warm cloak.
They agreed that the one who first succeeded in making the traveler take his cloak off should be considered stronger than the other.
Then the North Wind blew as hard as he could, but the more he blew the more closely did the traveler fold his cloak around him;
and at last the North Wind gave up the attempt. Then the Sun shone out warmly, and immediately the traveler took off his cloak.
And so the North Wind was obliged to confess that the Sun was the stronger of the two.
Including IPA for RP (“Standard British pronunciation”)
Including IPA for American pronunciation. (Note that the form “shined” is, IMHO, wrong (for the intransitive). It should be “shone,” as in the RP transcript above):
Bienvenida a italki!