My client wants me to complete the website. That’s not a problem. But there is not much copy for the pages. One page only has half a page worth of copy.
I have plenty of photos and graphics to work with.
Is there a design rule to use when dealing with a low amount of copy? You know, make the page look complete even though the content is lacking?
Is the content editable by the client (CMS?)? If it is editable I would just publish as is, when they see the problem they will (hopefully) complete the content.
Also, not all content is created equally. Some things take a few sentences to describe, some take pages and pages. If the existing copy gets the job done there’s nothing wrong with it being shorter than other copy.
I’d say the only rule here is to do what makes the client happy.
Who decides how much copy is too little? What you personally like or dislike may be the polar opposite of what your client and/or site visitors think is too much or too little.
If it’s something you feel can be added to another page on the site then suggest it to the client, but otherwise I wouldn’t worry much about it.
Ideally, design the site so that a page looks fine even with just a little copy.
No point in putting unnecessary content into a page just to make it look better.
It depends on the design, do you think the website looks empty with the copy you have on the page? The design should meet the content requirements.
I would say better to educate the client rather than indulge their delusions, keeping them happy won’t make their site successful. 
Surely if your a web professional, it’s your job to be able to make such decisions and know when a lack of copy will damage the site.
Well, I certainly make enough of my own assumptions around here, but these are a couple of big ones themselves Alex. Neither of us knows just what kind of site were talking about here and what successful means to them.
I think any good designer will try to steer his clients into doing whats best for them and their website, but it’s a rare occasion when they always go along with the suggestions made, and then you can either do what makes them happy - or say goodbye while they go find someone to do just what they want done.
Now I know I’ve seen studies that show that longer sales copy typically works better than shorter copy when it comes to sales letters, but I’ve yet to see anything that says not having enough copy on a page will “damage” a site - whatever damage means to you.
The only way to know with certainty what works for any website in any situation, is to decide what success means to you, then test and measure the results of different elements on your pages…everything from the colors and graphics to the copy used that can all have dramatic effects on the “success” of a website.
Personally, I think too many “web professionals” out there worry about the unseen things too much - while not putting enough effort into the copy and images used on the page that have a more measurable impact on the sales needed to keep a business afloat.
If this was one of my sites I wouldn’t be happy only filling half a page with content. But if you are getting paid I would go back to the client and let them know what you are working with and see if they want to write more content for the page. If not then i would just more forward with the project and get it done in a timely and professional manner.
Your client is either lazy or uneducated. Assume the later educating them and if the problem persists just get it done with what you have. Some people are just lazy and so long as they are paying are you might as well just go with the flow after educating them. Hopefully though they see the importance in content and give it either an effort or increase the budget so content can be created by an outside source.
Well, you can do some creative things like adding an exaggerated style to the headings, and indenting the body copy enough so that it extends down the page further. You could even play with the line spacing a bit. Basically, you’ll just have to experiment with a combination of several different things.
But like others have already said, you can just do it the way your clients want and cross your fingers that they realize how bad it is. But, my experience tells me that this will not be the case. 9 times out of 10 (for me anyway), the client is always happiest with what looks the worst. 
LOL… Spoken like a true, experienced web designer! For this reason I’m more and more getting a graphic designer to do the layouts, as it helps to dull the pain.