Especially in the beginning, make your bullion stitches with a firm yarn like Red Heart Worsted Weight.  The "soft" yarns can be much more difficult to maneuver. 

 Some yarns lend themselves well to bullion stitches.  My all time favorite
is Red heart Country Rose.  Country Blue works fairly well too.

Boye hooks seem to work really well, the space from the hook to the flat spot
allows you room enough to maneuver.  

Use larger hook to practice.

The key is to relax and yo loosely and evenly.  Yo around the shaft of the hook, not the narrow part by the hook.  The wrapped yarns should slide easily on your hook.  

Don't use a fresh skein of yarn to make a bullion stitch.  It is kind of
crinkly and will just make you split a stitch.  

Use yarn from the middle of a skein that is smooth.

If you do need to start over, smooth and twist
your yarn a little to help your hook go through the bullion easily.   

Can you make a hdc?  Then you will be able to make a bullion stitch.  The process is the same.  Think of a bullion stitch as a half double crochet gone crazy.

Practice adding a yo or two to a hdc.

Make first bullion in same st as the beginning ch 3.

You can unravel the beginning ch 3 stitch (in some cases), for instance when the beginning ch 3 is at the beginning round of a new color.  Unravel before joining with sl st in top of bullion.

The yo before the one you draw through should be even with the other yo's, being careful to keep it close to the working round.  

For the final yo that you pull through the other yo's, tuck the yarn fairly tightly under the hook and point the hook facing down, and pull the hook straight through the loops.  Wiggle the hook some, while holding the work with your left hand, pinching the base and long underside of the bullion stitch to steady it.

 There should be a long string to the left of each bullion stitch.  Be aware of the tension of this string, not too tight or too loose.  After you draw the yo through all the loops, pull it up higher and straighten the loops of the bullion stitch.  Then draw the working yarn back down to just the right tension.After you have drawn your final yo through the other loops, adjust the bullion slightly before you make the ch 1 that locks it in place.  After you make your locking ch 1, you can re-insert a size smaller hook into your bullion st to help you shape the stitch.

When bullions are completed, roll them gently with your fingers to tighten them up a bit.  The yo's should lie parallel to each other firmly enough to look like satin stitch embroidery.  

Use your tapestry needle to "clean up" your bullion, tacking the ch 3 behind the bullions.

Be careful when blocking bullions, you don't want to hold your iron directly over the bullion but rather work around it.  Always use a damp pressing cloth or use the steam setting on your iron from a distance of about 8 inches.  Your work can be smoothed and shaped somewhat while blocking.  

Red Heart Yarns hold up well to blocking and blocking makes the square soft and supple.  Practice on sample squares first.

If your bullions don't look great at first, then you are right on track!   The old Victorian patterns stated that you should expect to fail numerous times when attempting to make the bullion stitch.  Each time you fail brings you closer to success.

The best advice I can give you is to relax, and have fun with the bullion
stitches.  They do get easier with practice.