1. Get plenty of sleep! Your first year will be full of excitement, nerves, and other assorted feelings. Many will say the first is year is about surviving and while I had a great first year of teaching, surviving was definitely at the forefront. There will be many nights that you may need to stay up late to finish a lesson or get grading updated. If you are able to do so, taking a nap in the afternoon is perfectly acceptable. Also, while it is good to have a social life (or life in general), especially on the weekends, I recommend leaving plenty of weekends open so that you can rest and recharge. It seems like that first year of teaching or the first year in a changed assignment, is the year that one will come down with every malady under the sun. Sleeping and giving yourself time to relax will help combat that.
2. Overplan! Be very explicit with what is going to happen at each point of your class period. Especially for the first few weeks, I like to write out each segment of class, questions, approximates times, etc., and I have this handy while I'm trying to get in a groove with the new classes for the year. Have extra things planned so that if something runs short or doesn't work so hot, you have a back-up. Have things ready so that if you have five minutes left of class, you can do something with them. I have used different puzzles (thinking puzzles), both electronic and ones from books. I think this helps send the message that for the most part, you are going to be keeping them active for the whole class period. I've used Petals Around the Rose and the Stroop Test, as well as one-minute cases and various types of brain puzzles.
3. Be friendly! Something I was told in my teacher preparation program was to be friendly with the support staff. As a science teacher, it is especially important to gain the support of the custodians, as you may frequently have smelly or gross things at various stages of decomposition to be thrown out. Or you may need plastic bags for dissection, so on and so forth. Sometimes I hear people complain that the custodians don't dust this or wash that, but I have found if I specifically ask for something, they will generally do it in a timely manner. Maybe you shouldn't have to ask to have the paper towel dispenser refilled, but it happens. I have worked as a housekeeper in nursing home before, and I can tell you the job isn't glamorous and they are way more things for you to do than you possibly have time to do so. Be nice to your school administrative assistants. These people can make some things in your life difficult if you are a pain to deal with. They are often have a wealth of valuable information. There are others, I'm not listing of course, but you get the idea, be a decent human being.
4. Keep a hobby! Even though you are swamped with things, I think it is very important to make some time for something you have a great passion for, and/or it relaxes you or keeps you grounded. I love to read. There have been some years that I have read very few books, and I haven't felt like myself. I have tried to keep reading more, even if it isn't strictly a pleasure book. I feel more sane when I keep up with reading.
5. Lean on your colleagues! Most of them have been doing this for awhile. Seek help when you need it. Of course, just like in any other part of life, there are toxic people to stay away from, but many will gladly listen to you, give you strategies to use, etc. Many teacher preparation programs tell you to stay away from the teacher's lounge. For the most part, I haven't found our lounges to be filled with just all crab sessions. I don't eat in the lounge everyday, but sometimes it is nice to eat there or in another teacher's room to just get out of my head for awhile. Take advantage of social activities that your school plans or groups plan as well. I do have a bit of line, maybe more so than many colleagues, for what social activities I take part in or with whom, but I still look forward to many gatherings. Our school has a monthly "coffee" during the last part of our contracted time. It's a nice way to connect with others that you may not see as often. There are occasionally teacher parties thrown especially at the start of the year or the end of the year. For the most part, those are fun opportunities too. Just be smart and considerate about what you will be doing or partaking in while you are there.
P.S. Don't leave your copies to the last minute, because the copy machine will be out of service when you need it!