Put essential information first, name, contact details. You don't have to put date of birth, how many kids you've got or anything else irrelevant.
Consider then doing some kind of personal statement with a couple of sentences about what you are looking for from your next post and the key skills/experience you are offering, tailored to the job you are applying for.
Put your employment stuff next, starting with most recent. As you've been in the same company for so long you can separate out different roles you've had in the same way you would different companies. For each job give job title, possibly brief sentence saying what the job actually was - eg job was HR Officer, sentence could be 'providing HR advisory support to 300 individuals in 2 departments'. This is because a job title means different things in different organisation. Then do bullets for main responsibilities for each job, and also consider adding significant achievements in that job, if relevant - major projects/changes achieved, that kind of thing.
Then after your jobs put education and any relevant training. Don't put your school exam results unless you have just left university and have no work experience, which obviously is not you. It's irrelevant and looks like you are filling space. No one is going to give you a job because you got a C in GCSE geography 20 years ago.
Similarly I'm not a fan of putting hobbies etc unless directly relevant to the job you are applying for - again it looks like you are filling space and most decent recruiters will not shortlist on the basis of mountain climbing or bungee jumping unless they are after some tribunal experience following a discrimination claim by a disabled applicant or a single mother with 5 kids who doesn't have time for mountain climbing but is the best person for the job.
Don't make it too long, otherwise they will be skim-reading by the end - 2 pages is ideal.
Do lots of bullets and space it so it is very easy to read, long paragraphs and close-together small type are not inviting to look at, and won't be read properly.
Look at the key criteria for the job you are applying for, and tailor your cv accordingly to make sure these criteria stand out on your cv as much as possible - when listing experiences or responsibilities you had at a job, order them and emphasise them to reflect what the new job want.
Don't undersell your involvement in things. If you say things like 'helped with', 'assisted in', etc, people will assume your involvement and level of responsibility was minimal. Now is not the time to be all modest and unassuming.
Don't put a photo on, put it in a folder, do it on funny coloured paper or anything like that, it should be v easy to photocopy. And pages will become detached so number pages 1 of 2 or whatever, and put your name in the header or footer of each page.
hth and good luck with the search