It might seem obvious that you should photograph subjects and with methods which have been previously successful for you. It would appear that the opposite of the above is to never learn from our experiences and thus never advance as a photographer.
I think it is actually quite common for photographers to not even be aware of their strengths - or to put it another way, the strengths of their images. Sure the bigger problem would appear to be not being aware of their flaws, but in truth we need to work on both.
Both strengths and weaknesses in your images tend to show up when you hold up your work against that of others. This could be in a show, or simply at a camera club, or failing even that connection, holding up your work against what you find in magazines. Far be it for me to suggest you rip up your latest and pristine copy of Lenswork but it might pay to order an extra copy of one or two issues which feature work at least a little bit similar to yours. Remove individual pages and trim them, pin them to the wall next to similar sized images of your own - in other words have your own home show, your work and the published work side by side.
Workshops are an excellent way to get a sense of how your work holds up. Contests are not a good way - a few winners and hundreds if not thousands of "losers" which tells you almost nothing about your work.
Sometimes it's possible to sign up for a critique, or to have someone you respect look at your work, but you aren't looking here for a rating - this is how good your work is - rather you want to determine its strengths and with a bit of effort you should be able to determine these strengths for yourself.
Strengths can take a number of forms, from technical perfection to emotional impact, skills in composition, finding interesting subjects, the richness in your tonalities, the way you get your message across clearly and so on. Don't discount as a strength such simple things as wonderful colour, clever use of shadows, amusing images or simply being informative.
Having identified your strengths, it's time to think about what to do with this information.
Perhaps your strengths point to a particular kind of photography that would best make use of your skill set. Maybe your strengths are such that they apply to all your images, not some subset.Maybe now that you recognize your strengths, you can make them pay off more often. You might literally do an inventory of any scene to see how you could best use your strengths.
By the same token, you have to avoid or preferably overcome your areas of weakness. Do remember though that if you try to improve your strengths, it will take a lot more effort for much less return than if you work on your weakest areas, where there is so much room to improve.
My first book started with a series of articles on assessing your level in photography but in that we lump all your technical or aesthetic skills into one asessment. That concept remains valid but here I am suggesting that knowing the particular strengths (and weaknesses) of your images and yourself as a photographer can be of great help.