Here's an exercise to help you with holding eye contact with a man and smiling at him 3-5 seconds:

Before you leave your house, take a few minutes just to stand in front of
a full length mirror and gaze at yourself.

Get close to the mirror.
Look deeply into your eyes without looking away.

Look at the details of your eyes, and then at the details of your face.
Really know what you look like.

Now smile.
Practice different smiles.
See how you look giving each smile.
Feel the smile in the muscles of your face as you're smiling.
Close your eyes and smile.
Keep the image of your smile in your mind as you practice the smiles with
your eyes closed.

Now open your eyes and smile again, seeing if your smile is how you
remember it.

Now step back.
Look at yourself in the mirror from head to toe.
Admire how you look.
Look at the details of your clothing.
Step back even further from the mirror and smile.
Close your eyes and smile.
Do the same practice as above with smiling.

Now, when you are out and you see a guy who's noticing you, practice smiling at him.
If you can't hold eye contact with him for long, slowly look down as you continue to smile.
As soon as you can, raise your eyes and look at him.

You can also watch my free webinar that will give you more insight on
getting into your feelings in front of a man:

WEBINAR VIDEO (click below to access)