I am looking into the matter of grammar while teaching paired skills. Should we give equal share of focus to grammar in the same way we do with reading-writing and speaking-listening?
Grammar is erroneously classified as a skill; it's more of a knowledge of the rules of a language. That's why it gets into all the skills (the contrary is not true). The thing is that without focus on grammar a learner would perform inadequately and get into semantic tangles and misunderstandings. I am not here suggesting hyper-correction of grammar in teaching, but giving due value to correctness, and, at the same time, allowing for transitory grammatical errors in the learning process for psychological reasons.
In paired skills teaching, students' performance should be the prime aim, accordingly I support Krashen's viewpoint that grammar teaching should be limited to a few simple rules that may help students perform in different language skills.
In paired skill teaching writing is the most important quotient in learning proper grammar without mistakes. If the teacher focus on developing proper writing skill just like by giving them an unknown topic in which they have to write a paragraph, automatically it will enhance the knowledge of grammar. Again regarding speaking proper English ask the student to read what they have written in their copies and teacher can rectify their mistakes along with the pronunciation.
If you don't teach grammar, you don't give students a framework. Language-learning in school is not an acquisition-situation. There just isn't time for students to work grammar out as a child does. When teaching post-grads wishing to become language teachers, I used to give them some sentences in Welsh and ask them to work out the grammar. Nobody could ever get it right. You have to explain. Welsh shares features which students learning French would encounter, e.g. split negatives. It's also important to stress the difference between the grammar of the spoken language and that of the written version, especially in a language like French.
Rather than teach all the rules, you can also teach principles, e.g. for French, because of stress patterns, short words TEND to come before long words, e.g.
Je l'ai acheté; je lui en ai donné, and sentences build up to the longest elements. That's a principle, not a rule, so please don't come back with counter-examples. Another principle is that nouns ending in consonants TEND to be masculine. Nouns ending in '-e' TEND to be feminine (about 68%, I believe). If students know these principles they can apply them. See my article' Rules or principles? French grammar for A2.' Francophonie, 2014. Online edition.