Love, a mere castaway on my open shore,
Came only for a moment, and with time did drift.
Love, mirrored as a shadow that promised a forever,
And with time did fade.
^^ i would change a couple of things! just little things to : )
"Love, a mere castaway on my open shore. ((i put a period instead of a comma. you had a complete thought there so that's why i did that))
Came only for a moment, and with time, did drift.((i added a comma after time it helped this line make more sense to me))
Love, mirrored as a shadow that promised a forever,
And with time did fade.<<here i think it should rhyme with the line above it in the next stanza you have the last twolines rhyme i think it would help the flow of your poem if this did so to! "
Also maybe try to maintain the length of the lines it helps the poem not seem as choppy if the lines are relatively the same length
Ok now besides me just picking out what i thought needed a little toying with i thought this was a very beautiful stanza the words you chose worked well with each other they were compatible and i liked the repetition of love there. at first i was going to suggest taking the second love out but when i re read it i loved it : ) a little ironic i guess

As snow doth build upon itself to structure an image of beauty,
^^ i would maybe change structure to construct structure didn't quite fit the point i thought you were trying to get across : / this is only my opinion though! ultimately this is your poem

So did love.
Both melt away-
Simply love promised to stay.
^^ : ) great ending! very cute!

the only overall suggestion i have is to make the lines around the same length! other than that a beautifully composed piece if you ask me i like the message in it to : ) 5/5

You said this poem is under construction, so I will read what you have thus far and try to provide a few suggestions..

"And with time did fade."
`I noticed this line was very short and I thought that maybe if you made it longer to fit the length of the other lines in the first stanza the poem would have started off with a very nice flow, but with this line being so short.. it didnt ruin it too bad, but still your lines shouldnt be this short.. I think theres more you could add.

Second stanza, again make your lines longer.. having a really long line.. then three really tiny lines.. they didnt work very well. I know this is under construction, and I think you have an idea about what you wanna write just continue to work on this and piece together everything into a poem.

Good luck :]

I loved the poem girl it was cute;-)!!!!