I don't think you can plan too much before the NQT year. A year ago I was in that boat worrying through the last weeks of the summer about not having planned much as I didn't really know how to. Until you know your classes, your specifications and texts you are going to teach you can't really do much. lesson planning and marking takes absolutely ages in the first 2 months or so. I've become so much better at planning but marking still takes quite a while and I think that will always be the case until some clarification happens on how much marking is necessary and how exactly to mark.
The first month was a bit insane - you have that honeymoon period where your classes are testing you out. Looking back I got this month right with some classes but horribly wrong with others and I never really recovered from it. Anything you let slide in the first month will be hard to turn around. If you've allowed pupils to have earphones in, go the toilet often, talk over you without consequence then it will be incredibly difficult to turn that around as the year goes on.
The run up to Christmas is hard because the nights are dark, the mornings are dark and the term seems to go on for ever.
After that it does get easier in some ways. If you teach classes several times a week you should be able to build and form good relationships. You will make mistakes but you get to correct that mistake the next day. I taught quite a lot of one a week classes this year and that's been incredibly hard because you don't form that same relationship, you don't mark their books regularly, there's a loss of structure and pattern to lessons and the kids know on some level they can take the piss a bit and won't see you again for a whole week.
The best possible advice I think I'd give to someone starting this year is learn the kids' names s soon a possible. It's the most powerful tool for behaviour management. With my one a week classes I didn't learn names for absolutely ages and I'm a bit ashamed to admit I still don't know some pupils' names and there's just over 3 weeks left of term!
It's so hard to get the balance between authority and being fair and 'nice' to pupils. Ultimately I think I cared too much about being liked early on and let things slide. For some classes/pupils a stern approach just won't work but nor will allowing them to get away with things. It's really hard to do but I think a clear, consistent routine works best I.e they line up until you say they can come in, they stand behind chairs until you say sit down. If they talk over you their name goes on the board and so forth every single lesson every single week until they get the picture. On the flip side, rewards should consistently be given. Phoning home for positive news is one of the best things you can do - the kids love it.
With 3 weeks to go I've had all my observations and they've gone well so I'm now just looking forward to the summer and really coming back next year stronger. I know what to expect now, I can plan lessons over the summer and I can read up on strategies I've struggled with this year. I know it's not going to be plain sailing next year either but I feel better equipped for it all.
To new NQTs just enjoy the summer - as I said, you can't really plan extensively.