First of all, you need to take this slowly and steadily. Don’t panic over the bloody thing.
You’ve said that you’ve read loads. My tips are to check where you think you should score points for each of the descriptors. See https://www.citizensadvice.org.uk/Global/Migrated_Documents/adviceguide/pip-9-table-of-activities-descriptors-and-points.pdf for a table of the descriptors and the various activities associated with them.
You score once per descriptor and the aim is to score a total of 12 or more for each of the two components, Daily Living and Mobility. (For the enhanced awards, 8 points for the standard rates.)
I always recommend using the guides from the https://www.benefitsandwork.co.uk/ website. It does cost about £20 per year to join, but it’s worth it.
When you know where you think you should score points and how, you need to answer the various questions on the form. You should do this in rough first, or type them. I tend to leave at least a day or two between writing a draft and completing each question. So check the question, look at the guidance from Benefits and Work, check what points you think you should score, and write your answer with suitable examples. Then leave it for a couple of days before editing it.
I suggest you treat the whole claim process not as an antagonistic exercise. Pretend that a) the questions are reasonable and b) that you, the assessor and the DWP decision maker are all on the same side. You’re job is to explain to the assessor exactly who you are, what problems you have (in relation to the descriptors) and how your disability affects you. You also should try to give some specific examples.
Something people often say is that you should write your claim form ‘as if it’s your worst day’ I disagree with this, the reason I disagree is that if you do have to have a face to face assessment, and it’s not your ‘worst’ type of day, it appears to the assessor that you’ve exaggerated. By all means explain what a really bad day is like, but don’t be tempted to say something happens every day if it doesn’t.
You also need to gather evidence in support of your claim. This can take virtually any form. Letters from your neurologist, MS nurse, physiotherapist, carer(s), urologist, bowel and bladder nurse, GP, anyone else you see who can explain your physical and/or cognitive problems. Also, if you’ve had a social services assessment, or a care plan, include those. You can even include photographs of aids and adaptations you need. For each of the points you feel you should be awarded, you should have a piece of evidence to back up your statement.
Make sure you number every page you send, and have your name and National Insurance number on each. Don’t send original documents, photocopy the entire claim and post by recorded delivery. Don’t rush it, but also don’t miss any deadlines.
Good luck with it. (Sorry, this is a bit long, hopefully it’s useful!)