In one word: yes. Before we talk about how and what to use for your keywords first you need to work out your particular situation and what will work best for you.
For instance, if you are just keywording for your own use to find images easily in the future then that makes it fairly easy but if you are keywording for a stock image library, agency, magazine etc you need to be more specific.
Many agencies and stock libraries have specific guidelines and if your images are not keyworded no one will ever fine them, you’ll never make a sale and it’s a waste of time uploading them to the agency. These days it is important to find these guidelines and take note of the length of the captions and the quality of the key words used. For instance a stock library I submit to also has cartoons and graphics in it so the word photograph is very important in that collection of keywording. Many have limits on the number of keywords or total characters (this may or may not include spaces) you can use. If you exceed that then the keywording may be cut off and never be seen.
Take your time when keywording. Research what others have done: what works and what does not. Look at your image if you were a buyer: what would you type into a search engine? This is another reason captioning (which we’ll cover later) is important to be keyworder-friendly. Just because you think it’s a logical process does not mean others will.