Even if you are new teacher, I think, it is not other people who can do the "strategic" thinking for you. It is you who must do that in collaboration with your colleague teacher. I can quite well imagine and also appreciate the fact that if one is new to a school (and also perhaps to the teaching profession) one feels a little unsure and is a bit afraid while being highly motivated to do the best job one could ever do.

With this in mind, I cannot really outline from a distance what the strategy you may use should really look like. I perhaps can only provide some points that may be worthy of consideration when developing such a strategy yourself.

Writing is one of the 4 basic language skills - I am sure I am not telling you anything new. It is also not new that in language acquisition (native and foreign alike) the development of oral language skills always precedes that of written language skills. I think these are the 2 major points of orientation against you which must reflect everything you are planning to do and actually are doing. In this, my urgent advice would be to take a "holistic" approach - do not look writing at or speaking/listening separately but rather look at how they interact and how they may be connected in the learning process of your students.

To work with another co-teacher in the same class is a rare chance but is has it obvious advantages. Due to the functional interconnections among the 4 basic languages skills, one of you could perhaps concentrate on developing the oral skills that always precede the written language skills. Written language skills should always be based upon the oral language skills developed previously. Practically, that means to use the same vocabulary and structures in teaching written language skills that were taught with the oral language skills before and to expand further from on the basis of that. You may slightly vary the topic and activities but you should be careful not to introduce too many new vocabulary and structures not taught in the oral language skills before. Adjust topics, vocabulary and structures covered, and the learning activities to what your students already know.

For lesson plan development, discuss with your co-teacher in class. This is a start, I think. The rest will follow from your experiences at a later point of time after you have come to know your students and their individual language skill levels. In my country, we have a proverb: "The beginning is always difficult". But as time is passing by things will become easier.

Good luck!