Light meters are, in my opinion, almost as important as the camera itself. Yes, there are times that I don't use mine, but those are very rare. I can't recall a time that I didn't use it when in studio.
As for your progress, I would work on your lighting setups. There are a lot of good tutorials around the web on how to set up your strobes to produce different effects and a lot of them are free. There are also some very good books on lighting.
In the first shot, I think that the model's right side (our left) is exposed well, however, her left side (our right) is dark. Personally, I would place a reflector to her left to bring more light in on that side (a white piece of foam board from Office Depot worked for me once). Also, there isn't much definition in her hair. Another light focused on her hair from above and to the rear (in this case behind to the left of her - our right) would give more highlight to the hair and make her pop out of the shot more. You would have to be careful doing that with this shot, however, in making sure that you don't create a hot spot on the hand that is in her hair.
To sum up, I think the two best investments that you could make right now would be a light meter and a book on different studio lighting setups. As mentioned, the light meter is something that you can't live without when shooting in studio, especially when using strobes. As far as a book on lighting setups, I am constantly looking for new ideas, so I am forever looking at these types of books!
My biggest suggestion is to keep working on your technique. Getting to a point that you have consistant shots takes time. I have been shooting studio for about 5 years and am still learning. I am sure that there are photogs that have been shooting studio for a lot longer than me that will tell you the same!
Here is an example of Ashley using multiple lights (these were hot lights and not strobes, but the theory of lighting remains the same).
You can see the highlight on her hair on her left side (our right) from the hair light that is on that side. This seperates her from the bg and gives her hair more detail.
Those are some of my suggestions...keep working on it...you are going to get there...just practice practice practice!