Above is a picture which shows what I consider to be the bare minimum of essentials to take to lectures with you.
First off we have a drink- ideally this will be something simple like water or sugar free juice as I found drinking sugary drink left me having a sugar crash and becoming lethargic after an hour, not ideal when you have 2 or 3 lectures in a row. A drink is also useful if you develop a cough during a lecture (trust me, it happens) as the last thing you want to be is that annoying kid who is coughing so loud nobody can hear the lecturer.
The next thing I recommend you take with you is a diary, in my case I use a Filofax, but lectures will often mention things like useful documentaries to watch (I do a science degree) as well as upcoming deadlines and exam dates :)
Next you will need a pen, I carry two- a 4 colour Bic pen so I can easily add colour to my lecture notes without rummaging through my bag and I also carry a free pen that I got a freshers fair in case somebody asks to borrow a pen.
Finally I have a notebook to take my lecture notes in as this keeps them all together. I use the same notebook for all of my modules as I tend to rewrite my notes up when I get home so carrying multiple notebooks just added unnecessary weight to my bag.
Other things that people like to bring to lectures is a voice recorder so that you don't miss anything said in lectures, although maybe wait until after your first week of lectures to invest in one of these as some universities use programmes like 'Panopto' which record the lecture for you and are then uploaded online.
Some people also like to print off the lecture slides in advance and take those with them as well.
Finding the best system for you to take lecture notes is a process of trial and error and some university students don't find their 'perfect' system until their last year of study, so don't get frustrated if you find the method that you used at sixth form and have been planning on using all summer falls short in your first term. Just evaluate what your current system is lacking and try to implement these into your next system to trial.
Lastly good luck! The transition into lectures can take some adjustment, so if you have any questions then comment on here or email me at firstname.lastname@example.org and I will do my best to answer your query :)