If you are a learner of a language that is not your mother-tongue, this is a pretty effective way to spot your strengths and weaknesses and build on them. You can also see your progress in certain ares and aspects of the language such as reading and speaking easier using this tool. Here is what you need to do:
Record yourself, especially your voice. Even though video recording is beneficial in certain areas, for this activity, I would prefer only an audio recording to eliminate the risks of being distracted with other things such as the way you look or act while talking.
While doing some self-study, just turn on your voice recorder and start reading out loud or pretend to be giving a presentation or a speech. Don't record yourself for more than 10 minutes. It should be only for a few minutes at a time to be able to pay extensive attention to details while listening to yourself. Listen to yourself again and again and see what you can spot: Any grammatical errors? How is your vocabulary, pronunciation, stress and intonation? Do you have some fluency issues? etc. Your own judgement would be limited but still very helpful.
If you have the luxury of having a teacher, a friend or a family member who is competent in your target language within your reach, see what they think of your recorded piece too. Their feedback is likely to be very valuable and help you improve your language skills. You may even leave it for a while and go back to it later on and you may be surprised how much of a difference you see in your current skills compared to the ones that were recorded at the time or that you may be able to analyse your own language skills better.