Hi Hannah,
I gave up smoking nearly 3 years ago - I felt so **** I decided I had to do something. Turns out I was an undiagnosed T2 with staggeringly high levels, but that is a story for another day. Anyway - tips and tricks I discovered when I gave up - which took me about 10 weeks in total.
1. You do need to want to give up / be in a frame of mind that this is the ultimate goal is to not smoke. Prepare your head that is not going to happen over night but it is more than doable.
2. I initially started by getting a disposable e-cigarette and deciding to use this one instead of real cigs, so over time I weaned myself off real cigarettes and replaced them with the e-cig instead. I chose to use a disposable e-cig as I did not want the "investment" in the liquids, cartridges, chargers etc., as this would mean to me that I was still prepared to investment money in smoking / vaping. (I still think e-cigs are a good idea however, whether they are disposable or not).
3. The biggest thing I found was that I had to change my reaction to events that caused me to reach for a cigarette. For me this was tricks such as having a glass of water, going and cleaning my teeth, going for a walk round the block, going for a cup of coffee, but in the canteen, not outside. I chewed gum rather than snacked. I bought a pocket puzzle book and would whip it out and do a quick soduku instead of a cig. I would reward myself with a non food treat for getting through the week. The tricks you come up with need to suit your environment.
4. I use an App to track my progress and at the beginning I used it alot to motivate me to keep going. At the moment it is 980 days without a cigarette, I have not smoked 14708 cigarettes and I have saved nearly £7000. (I used Cessation Nation on Android)
Anyway - overall I did not suffer any serious withdrawal symptoms and when I have spoken to other ex-smokers they have often said the giving up was not as bad as they thought it would be. On the other hand I had sky rocket high BS numbers, so it is possible they masked the symptoms, but I did not have the coughing lungs up that I expected. I wont deny there are days when I miss the action of having a cigarette, but I whip out my phone have a quick look at my app and that usually does the trick for me.
There are different ways to give up - it is a case of finding the one that best suits you. Get the info pack from Stoptober
https://stoptober.smokefree.nhs.uk/
Alternatively if you want to try an e-cig you can get a free sample at
http://www.vapourlites.com/electronic-cigarette-free-sample.html
Lots of luck
. I gave up for a few years back for a full three years using hypnotherapy...which was a lot easier than I thought it'd be...but not for everyone. I wish you the best of luck in whichever method you choose...and let us know how you get on...a good success story will hopefully kick my **** into gear 
but I needed it as I lost nearly 2 stone in a year from what I don't know (maybe a COPD related thing) 