From my experience, you can improve the four French skills by working in the following ways:
To write better, you must read. This will allow your brain to photograph the written syllables (or graphemes) and thus the spelling of words. Moreover, you will enrich your vocabulary with new words and expressions.
Work on your grammatical structures and remember the turns of sentences and their construction as well.
To speak, it is necessary to listen and to reproduce the sounds heard (spoken syllables) or also called phonemes. Your mouth, lips, tongue and even throat will become familiar with the new sounds. You have to train by pronouncing the word or the sound several time.
And of course, practice with a French native teacher or a French person who is able to explain the construction of the sounds and the rules of the pronunciation associated to.
To understand a French person, you have to listen and hear the sounds that make up the words. Hearing will get used to the different accents and tones of the voice. It is therefore necessary to work on listening with all types of media. The more you are in contact with dialogue situations in French, the better your listening comprehension will be.
To improve the reading, you have to pronounce the syllables correctly. For this, you should work on your pronunciation (know your alphabet, the different existing sounds) and know how to break the words down into syllables. This will help you find the correct pronunciation for difficult words. Take your time to read, it will let you see the next word coming.
I hope these tips will guide you in your process of learning the French language.
This is my personal opinion taken from my teaching and learning experiences.
Merci pour votre attention et à très bientôt !
Le Français For You
Love, Learn & Share