Dear Lyncca:
Your efforts for a first sitting are to be complimented. I think you have a bright future. I would like to offer some comments that you may find helpful. As always, when I critique a print, it is from the perspective that the image was intended to be a professional portrait that would be sold to a client. I will focus mostly on the first image with perhaps a reference or two for the others.
You do seem to be having color shifts from one image to the next. This could be caused by a number of things but since you didnt mention what you used for lighting or what the setting was like, it would be hard to speculate. If you are working in your camera room with no light other than your studio strobes, then you should see consistent color unless you are working near a wall or other colored object that is reflecting colored light back in the direction of the subject.
When working with any portrait subject, we must keep in mind that we are photographing a three dimensional subject that is to be viewed on a two dimensional medium. In other words, a flat photograph. It is necessary to create three dimensional contrast that will tell us what the shape of the subject is even though it is seen as flat art or an image on a flat screen. In this case, your subject is pregnant and very definitely a three dimensional subject. In order to show this properly, we need to have the tummy pointed in some direction other than the camera in order to grasp is shape more readily. In most of your images, the tummy is point pretty much toward the camera so we never really get to see its shape as much as we could if she were posed to more of an angle. For this kind of portrait I usually dont recommend working on the floor or in a reclining position as the tummy can look distorted or lean to one side. Laying her on her side and pulling her shirt up, could easily be improved on by showing her seated or standing at a slight angle with him posed near to her showing some affectionate connection between the two.
Another area of concern is the lack of separation between subject and background. The man is wearing black and you have used a solid black background without any separation light. Unless we are going for some sort of special effect, its important to separate the subject from the background. A painted background or the use of props can help in this area. A gentle hair/separation light would also aid in bringing the subjects visually away from the background.
Clothing selection is important in portraiture as it creates a sense of harmony within the image and allows the subject to be presented without distraction. In your image, we have a bit of a conflict. The colors are well chosen but she is wearing long sleeves and he is in a tank shirt. One suggests warm weather while the other suggests cooler weather. Try to keep things similar so you have consistency. In all things there are exceptions and there are many fine contemporary portraits that break from traditional portrait guidelines but in this case, you would have done better keeping them both in long sleeves. Arms and wrists are generally not the most attractive parts of the body so keeping with long sleeves is a good general rule. Compliments on staying with solid colors.
Also, when you expose a great deal of skin such as arms, it pulls the eye of the view away from the face which is usually the most important component of the image. Note that you also used long sleeves on the girl in the second image and he is still in a tank shirt. Additionally, you have a low key setting and in the second image, she is wearing white. We would call this a conflicting key. White is brighter than the flesh colors so it will draw the eye not to mention showing wrinkles and making the subject look larger than they are. White clothing is fine for doing high key work but generally speaking, we keep with low key clothing for low key settings. Also observe that she is wearing dark denims while he is in light denims. Not Earth shaking but it would be better if he were also in darker denims so as not to draw attention to that area. Visualize this couple in matching dark denims and long sleeve dark red sweaters or shirts. The focus of the viewer will instantly go to the faces.
Also, the purple flower does not add to the image. There is no real purpose for it and it is a conflicting color with what the girl is wearing. There is an old saying that holds true even today. If it doesnt add, then it probably takes away. This is the case with the purple flower that does not blend well with the deep red shirt.
Another observation in the first image is how little of the man is actually seen. In portraiture, we try to have the man looking larger than the woman. Note that you also cut his chin off behind the girls shoulder.
Note in image number two that her wrist is severely bent back to support her head. It is also much brighter than her face. Having her slide it under her neck and then arranging her hair around it to cover it up would be more pleasing to the eye.
Overall, your lighting is coming along. Note however that in image number two, your main light is actually coming from below her eye level somewhat like halloween lighting. In this case it is acceptable but if your ratios were not controlled as well as they were, you would not be as happy with the look of the lighting. Portrait lighting generally comes from a position above the axis of the face which in this case would be above her head and slightly behind her. It would have lit his faces left side rather than the right and kept his face brighter than his arm which in this case is closer to the light source and therefor brighter than his face. We generally want the faces to be the brightest flesh areas in our portraits and as with many other things, its always better to get it right in the camera rather than having to spend hours working on it after the fact.
I hope you find my comments helpful. Feel free to write to me should you need help.
Best wishes,