I can't help feeling that there's a couple of shots missing from my portfolio, but not sure what.
What sorts of shots would you say I need to contribute to my portfolio in order for it to be successful?
Well, first of all, who says your portfolio is not 'successful'? It shows you off pretty well... I don't think many photographers would pass on you because of your portfolio.
What would I suggest as additional shots? Shoot some full length stuff standing at a 45 degree angle to a line between you and the camera wearing some well fitting casual clothes (translation - show off your figure!), and looking into the camera.
Maybe a few shots sitting, kneeling, or squatting with one knee down on the ground in casual clothes. Adds a little visual variety.
EDIT: Well, your profile says you don't do nudes... but the 'credited images' link in your portfolio says otherwise as do a couple of shots in your portfolio. Maybe, you missed those?
Oh, and MM finally caught up with your avatar. A little too much bottom showing I suspect...
I agree with others that you have some gorgeous pictures in your portfolio. Photographers would be thrilled to work with you.
My primary suggestion is to branch out from some of the perfect model types of shots. In each of your shots, you look nearly perfect. Get some variety of expressions and activities. Outdoor shots or possibly other props like elegant furniture.
I'd keep #s 1, 4, 5 & 10 of your current crop, then add some variety according to what your modeling intent is . . . you should also take a look at some good comp cards, and fill out the image needs to create one of those, an E-comp card is any easy way to send something to potential clients, and give them a quick overview of your look . . . they're also printable if you have them in a PDF form . . . nice look, and shape, not sure you've shown either off to their best levels as yet . . . add some variety, and a really good head shot . . . you've got an open invite to shoot if you're ever over in this direction . . . much continued success!!!!