First off, let me start be explaining that Acrostic Poetry is where the first letter of each line spells a word, usually using the same words as in the title. Pretty straight forward, no rhyme scheme or syllable count is needed. There are several types of Acrostic poetry: Acrostic, Double Acrostic, Slant Acrostic, but as for now we'll stick to the plain and simple Acrostic style.
Alright, now that you know what an Acrostic poem entitles, it is time to get started on writing one. The first thing you want to do is decide on a title, now I know a lot of you dread coming up with a title first, but for this style it is necessary. Once you have decided on a title you can set-up your poem. By set-up your poem I mean doing this... For example, if you choose the title, "Within My Heart" you would set-up your poem like this:
This ultimately spells out the title of the poem vertically. Now that you have "set-up" your Acrostic poem, you can get started with the actually writing portion of it. When writing the poem, it is sometimes difficult to think of a word that starts with that letter, therefore; writing a list of words that start with that letter, or googling will help. For example, if you where stuck on the letter "E" you could google, "words starting with e" or write a list of words that you know start with "E"
List of words starting with "E"
Embarked, Embedded, Entitled, Enlisted, Evolve, Educated, etc.
Once you have finished writing the poem, I highly advice you to re-read it; for it is a given with anything you write, there will always be mistakes. You will most likely find mistakes, whether it is spelling or the flow of the poem, mistakes will be there. Once you have fixed all your mistakes and have re-read it again and again till it sounds nearly prefect to you, then it is finished and time to be constructively criticized by other poets on the site.
Most of all just have fun and enjoy the style in which most of us where taught when in school at a very young age. They usually made you do it with your name or someone else's name. Just relax, have fun and enjoy the beauty of writing.