Here is a very nice site with a worked example of how to write blank verse.

Scansion of "Need a nap"

It's lunchtime, drowsy, sitting quietly here.
o     B    o      B  o   B  o     B-o-   B
A warm burrito's drained my brain away,
o  B    o  B o     B      o   B   o B
digestion slowing thought and busy work.
 o B  o     B o     B     o    B o  B

Need a nap

It's lunchtime, drowsy, sitting quietly here.
A warm burrito's drained my brain away,
digestion slowing thought and busy work.

This is my scansion of Dryden's "The Presbyterians". Dryden is easy to scan -- he wrote pretty strict heroic verse. You may ignore the % signs, they are to mark comments in the typesetting file I did this in (LaTeX), or, think of them as marking the scansion lines.

I didn't scan the whole thing, finish it if you like:

More haughty than the rest, the  wolfish  race
%o    B    o   b    o  B      o   B   o     B
Appear with belly Gaunt and famish'd face:
%o B    o    B  o  B    o    B o      B 
Never was so deform'd a beast of Grace.
%B  -o-    B  o B     o  B    o    B 
His ragged tail betwixt his leggs he wears
%o   B  o   B    o  B    o   B     o  B 
Close clapp'd for shame, but his rough crest he rears,
% o     B      o    B      -o-    B  *   B    o  B 
And pricks up his predestinating ears.
%o    B  * B   -o-    B  o B o   B 
His wild disorder'd walk, his hagger'd eyes,
%o   B    o B  o     B     o   B  o    B 
Did all the bestial citizens surprize.
%o  B     o  B   o   B o b    o   B 
Though fear'd and hated, yet he ruled awhile,
% o     B     o    B o    B   o  B    o  B
As Captain or Companion of the spoil.
%o  B  o   b   o  B o   b    o   B
Full many a year his hatefull head had been
%o    B -o-  B    o   B   o    B    o   B 
For tribute paid, nor since in Cambria seen:
%o    B o    B     o   B    o   B   o   B
The last of all the Litter scap'd by chance,
% o  B   o  B     o  B  o    B     o   B
And from Geneva first infested France.
%o    b   o B o  B    o  B  o    B 
Some Authors thus his Pedigree will trace,
%o   B   o     b   o   B o  b   o     B 
But others write him of an upstart Race:
Because of Wickliff's Brood no mark he brings
But his innate Antipathy to Kings.
These last deduce him from th' Helvetian kind
Who near the Leman lake his Consort lin'd.
That fi'ry Zuynglius first th' Affection bred,
And meagre Calvin blest the Nuptial Bed.
In Israel some believe him whelp'd long since,
When the proud Sanhedrim oppress'd the Prince,
Or, since he will be Few , derive him higher,
When Corah with his Brethren did conspire,
From Moyses Hand the Sov'reign sway to wrest,
And Aaron of his Ephod to devest:
Till opening Earth made way for all to pass,
And cou'd not bear the Burd'n of a class.

Dryden, John. "Presbyterians, The" The Columbia Granger's World of Poetry.

Beat-offbeat scansion of "The Pilot"

As an example, look at the following. You may wonder about my virtual offbeats, well I was trying to figure out the metrical pattern. This is a tetrameter poem, with a lot of feminine endings.

I typeset this with the HTML pre / pre tags. I hope all the lines are there, this web-based editor is a little jumpy. Note that the symbols come under the vowels.

Here is my beat-offbeat scansion of

The Pilot

From the Past and Unavailing
 B    o  B   o   b o B  o
After groping, after fearing,
B  o    B o    B  o   B  o
Into starlight we come trailing,
B  o   B  o     b  O     B  o
And we find the stars are true.
b    o  B     o   B   o     B
Still, O comrade, what of you?
 B    o  B  o      B  o   B
You are gone, but we are sailing,
B  o    B     o   B o    B  o
And the old ways are all new.
b     o B[o] B   -o-      B
b     o B    o   b   O    B

For the Lost and Unreturning
b    o  B   o   B  o B  o
We have drifted, we have waited;
B  o     B  o    B  o    B  o
Uncommanded and unrated,
b  o  B  o  b   o  B o
We have tossed and wandered, yearning
b  o    B     o    B  o      B   o
For a charm that comes no more
b  o   B     o   B     o  B [o]
From the old lights by the shore:
 b    o B *  B     -o-      B [o]
 b    o b    O     b    o   B
We have shamed ourselves in learning
b  o     B    o   B     o   B   o
What you knew so long before.
 b   o    B   o  B    o B

For the Breed of the Far-going
b    o   B   -o-     B * Bo
Who are strangers, and all brothers,
 B o      B  o    B   o     B  o
May forget no more than others
B   o  B   o  B     o  B  o
Who looked seaward with eyes flowing.
 B  o      B  o    b   o     B  o
But are brothers to bewail
B  o     B  o    b  o B
One who fought so foul a gale?
B     o  B      o  B   o  B
You have won beyond our knowing,
 B   o    B   o B   o     B o
You are gone, but yet we sail.
 B  o    B     o   B   o  B

--Edward Arlington Robinson.

Utility post: about beat-offbeat scansion

Rather than try to write this in iambic pentameter, I'll just use ordinary prose. I like Attridge's beat-offbeat scansion mainly because it is easy to insert between lines when typing poetry. I will very briefly summarize it, and include my own suggestion for a typographical modification:

The following go below the line of poetry:

• Beats:
• B -- Emphasized beat (stress),
• b -- Unemphasized beat: normally unstressed syllable falling on a beat position in the meter,
• [B] -- Virtual beat, an "unspoken" beat that we tend to sense when say, three-beat lines alternate with four-beat lines (tetrameter alternating with trimeter, as in many ballad forms.)
• Offbeats (where the typography gets hairy):
• o -- Unemphasized offbeat, "standard" offbeat.
• O -- Emphasized offbeat, normally stressed syllable in offbeat position.
  
• -o- -- Double offbeat, common in iambic substitutions, dactylic and anapestic rhythms. If one or the other is a bit more stressed, use =o- or -o=.
• ~o~ -- Triple offbeat, rare in strict metrical English.
• ^o or * --Implied offbeat, rhythmical pause between stressed beats. I think of this as the "missing beat in the middle of a spondee" to relate it to more traditional scansion. I suggest the asterisk as easier to type and more compact.
• [o] -- Virtual offbeat, generally found at a caesura or grammatical pause, another "unspoken" one.

The o-caret combination is nasty to type, so that is why I propose the asterisk instead. For completeness, here are Attridge's "Rhythmic figures" with a comment or two. Following Meter and Meaning, # marks the beginning or end of line, // a signifcant break in the line:

1. o b o
   o b #
   # b o
   Examples of unemphasized syllables acting as beats, aka "promotion."
2. B O B
   # O B
   "Demotion", analogous to above.
3. # B -o- B
   // B -o- B
   "initial inversion" and "medial inversion", in traditional scansion a "trochaic substitution."
4. -o- B ^o B or -o- B * B
   "offbeat initial pairing" traditionally: "pyrrhic and spondee, double iamb, ionic minor."
5. B ^o B -o- or B * B -o-
   "beat-initial pairing" traditionally: "spondee and pyrrhic, ionic major."

And that's the system. I'll post an example or two next.

Ideals and rules to follow posting here

A quote:

Iambic five-beat lines are labeled blank
Verse (with sometimes a foot or two reversed,
Or one more syllable--"feminine ending").
Blank verse can be extremely flexible:
It ticks and tocks the time with even feet
(Or sometimes, cleverly, can end limping) . . .
--John Hollander Rhyme's Reason.

An alexandrine fits the plan a time or two,
while substitutions should be less than ten percent,
and Beat-offbeat scansion's favored here,
for ease of cut-n-paste and mousey edits.