Hi, I'm a new esl teacher, and I work for a brand new school with no textbooks or curriculum for ESL. The students I teach seem native speakers, but they have weaknesses in writing and spelling, as well as grammar and punctuation concepts. What is a good approach to teaching them? Also, keep in mind, I don't have books, and might not get any for a while. I'm also open to book suggestions for next year. thanks!:)

The first thing you need to do if your school hasn't done it is assess where you want your students to get in terms of achievement. You cannot just teach them any topic to fill up time, you should know which objectives you want them to reach. You don't mention your students' age or reason for learning English, this is a good place to start. I have taught ESL students in different environments and I have had to adapt my planning to what my students needed. When I worked with adults they were very worried in being as grammatical accurate as possible when talking and reading; when I taught teenagers they wanted more than anything to "sound" as native as possible, so what I did was adapt my planning to give them what they wanted.
Once you have identified your students' needs and interests you will have an easier time looking for material in books and in the internet.

Well first you have to get them use to the concept of reading and writing, so they get use to it, ask each of them to borrow a book from the library, (depending on their age level) have them read outloud to you, correct them if they read a word wrong, stop them occasionally and choose a random sentence that they just read and ask a question about it like, what is the subject in this sentence. This helped me when I was in ESL, now i speak great english and i know all the grammar and punctuation.