The glass dildo measures approximately 6 3/4" (insertable length of 6") with a diameter of 1".
The bullet measures approximately 2 1/4" with a diameter of 1 1/8". (This isn't ideal for insertion, this is more of a finger vibe.)
The anal plus measures approximately 2 3/4" (total insertable length) with a circumference of 3 1/2" at it's the biggest part.

The glass dildo is perfect. It's a nice width which is perfect for beginners. Personally, I think this is a wonderful addition to any beginners toy collection. It has a great flared base and light ribbing for extra sensation.
The bullet vibe came with a rubbery sleeve with a small loop for you to slip it over a finger. I wouldn't recommend using as a cock-ring as it wouldn't fit or feel very comfortable.
The anal plug (my FAVORITE piece) is also a pretty standard size. Maybe not the smallest choice for a beginner, but it's not the largest option either. I love the crystal on the bottom, with the gold color it's definitely fit for a princess.

The dildo and anal plus are both very simple to use. Simply use a little lube and slip it in. The glass dildo is a wonderful addition to any toy collection as it has many versatile uses. Glass toys are amazing for temperature play: you can warm it up or cool it down.
The vibe is where I had a less than ideal experience. Upon opening, I noticed it didn't turn on which is what I was hoping for. I opened the battery cover and removed the little piece of paper that was resting on top of the battery. I love this little precaution to ensure your batteries don't run dead.
However...mine didn't work. I took the batteries out, flipped them around, put them back how they were and nothing. I was so disappointed. I wanted this little toy to work so bad as I was hoping to use all three toys at once.
Other than that little issue, the set is wonderful and so easy to use.