One word doesn't given us much, so let's start with two words:
The evening
Now, obviously, the question is, the evening what? And there are two obvious paths we can go; we can take evening as an adjective, or we can take it as a noun. If the former, among the very salient next words are 'breeze' and 'star'; if the latter, two of the obvious next words are 'is' and 'falls'.
One of the things you do in writing poetry is to take a road less traveled and deliberately avoid the easy word, feel your way to something and then avoid it, and it will be worth contrasting this with just feeling your way through. So for the moment let's instead do:
The evening wolf
And the obvious question is, the evening wolf what? Now that we definitely have a noun, it begs for a verb. 'Is' is still possible; 'howls' is obvious. Let's break away from those and say instead:
The evening wolf breaks
Now, I've deliberately picked this verb because it's an odd one; you need a kind of breaking that a wolf can do, which limits what can go next. Two obvious possibilities are 'out' (as in breaking out in a howl) and 'cover'. Perhaps we can twist slightly again and say,
The evening wolf breaks silence
Now, we can compare that with the case in which we tried to go the easy way. So
The evening star
What do stars do? They shine.
The evening star shines
What's the next word after shines? Probably 'down'.
The evening star shines down
You usually don't just shine down, though, you shine down on something.
The evening star shines down on
On what? We could get a noun next, but it's probably going to be 'the' + something.
The evening star shines down on the
What do evening stars shine down on? The world.
The evening star shines down on the world
We could leave it there, but there's an obvious next word,
The evening star shines down on the world below
So let's pause here. It's a very pedestrian line (by definition, since taking the linguistic path of least resistance is what it means to say that something is pedestrian in poetry), which is not to say that it is a bad one; a poet who wrote lines like this would probably be trying for larger-scale effects -- big descriptive scenes, juxtaposed images, narratives, thematic repetitions, slowly building metaphors or twists. You often need pedestrian lines to make larger poetic structures easier to pick out. It's very difficult to do large-scale poetic effects Sagrada-Familia-style, with nothing normal in the details and yet a clear structure to the whole. So if you started here, you might use a structure like:
The evening star shines down on the world below,
which, covered with the freshly fallen snow,
shows tracks, deep black, of wolf and hare,
that punctuate the paper white and bare;
and so on, narratively, each line usually being the sort of thing that on its own could be found in a prose description or narrative, just arranged so that you keep the rhyme. The evening star shines down on the world below is a storytelling kind of line.
With The evening wolf breaks silence you would probably be doing detail-work -- capturing a particular image or metaphor or aural effect.
The evening wolf breaks silence,
the clouds unveil the light
which howls with silver violence
against the shades of night.
But what I am doing in showing how you might go from the original line is another act entirely different from feeling your way; I am identifying a function for the poem and engineering a way to incorporate the lines into a mechanism with that function. If you just feel your way forward, it works very differently. You know, for instance, that you are eventually going to go off the road, just as you know you would if you were blindfolded on a real road. But just by feel you can get quite a bit. For instance, evening stars shine down on the world below, but in poetry they also shine down on snow, and there are likely many, many poems where below calls and snow answers, so you can feel that a line after one that ends with 'below' is likely going to have 'snow'. If you're writing in English and used to poems that rhyme in couplets, one way to go from line to line will be boustrophedon, taking your words left to right in the first line and then taking them right to left in the next, then back to left to right. (In practice, of course, you sometimes might be feeling your way in both directions, sometimes left to right, sometimes right to left, just as the spirit takes you.) So we have
The evening star shines down on the world below
snow
and it's very unlikely that you would just have the lines like this! The natural thing is to have something in front of 'snow'. What is often in front of 'snow'? 'Fallen'.
The evening star shines down on the world below
fallen snow
And what's an obvious thing to come before 'fallen', when you are talking about stars and snow?
The evening star shines down on the world below
freshly fallen snow
A few more moves and we might well get something like my two first lines above:
The evening star shines down on the world below,
which, covered with the freshly fallen snow,
Just by feel you might get the tracks in the snow, and the wolf and hare (which often make tracks in snow, and might be naturally paired); it's just possible that by feel you might get the paper from the white and snow, but unless you've come across the image before, you probably would not get the punctuation on paper because it's not common and requires combining several different comparisons simultaneously. When crafting a poem, that's exactly what you might use easy lines for to lay out the obvious things that you then twist all together at once. If you're not crafting, you're never going to get a twist except by accident. (Such accidents do happen; as I've noted before, there is a purely aleatory component to every kind of art. One of the things you do if working by feel is to keep an eye out for such happy accidents.)
You could go on by feel for as long as you please, but in practice you would usually not do so unless you were writing something very short, because of the fact that you will inevitably go off the road. As I have no great poetic genius, a lot of the poetry I write is just my experimentation with this or that, so I do lot of first drafts mostly by feel, and inevitably at some point, if you have a meter, you get off it, if you have a syllabic count, you deviate from it, if you have a rhyme scheme, you lose it. Do it with anything very long and you start sounding like William McGonagall, who is the master of going on and on as purely on the basis of feel as you can go while somehow still getting something completely recognizable as verse:
As soon as the catastrophe came to be known
The alarm from mouth to mouth was blown,
And the cry rang out all o'er the town,
Good Heavens! the Tay Bridge is blown down,
And a passenger train from Edinburgh,
Which fill'd all the peoples hearts with sorrow,
And made them for to turn pale,
Because none of the passengers were sav'd to tell the tale
How the disaster happen'd on the last Sabbath day of 1879,
Which will be remember'd for a very long time.
It must have been an awful sight,
To witness in the dusky moonlight,
While the Storm Fiend did laugh, and angry did bray,
Along the Railway Bridge of the Silv'ry Tay,
Oh! ill-fated Bridge of the Silv'ry Tay,
I must now conclude my lay
By telling the world fearlessly without the least dismay,
That your central girders would not have given way,
At least many sensible men do say,
Had they been supported on each side with buttresses,
At least many sensible men confesses,
For the stronger we our houses do build,
The less chance we have of being killed.
