A few things I’ve noticed on this thread;
Put the schools in the order you want them
Other posters have said this, but it’s so important - you will not be negatively impacted by putting a school second. The schools don’t get to see what order you’ve put them in, and if you don’t get your 1st choice, your 2nd choice will be treated as if your 1st choice.
Filling in the form
It is illegal for schools to ask for information about, eg your child’s interests. The only exception is for faith schools where the admissions policy may include an element of church attendance (but not, eg, whether you are on the PCC, or are a server or a flower arranger). Admissions are done on a purely objective basis, and decisions are not made with discretion; the policy is applied and this will produce the list of offers.
Choose at least one realistic option
When you’re choosing your 3 schools, make sure one of them is a school that you have a good chance at - eg don’t put 3 lottery schools down - assuming that there is 1 that you are happy for them to go to. If you are not happy for them to go to any ‘possible’ school, then don’t put it down, because at appeal they will ask you whether you were allocated any of your options, and if you say ‘yes, but it’s impossible for them to go there’ then that doesn’t look good.
Appeals information
You are trying to prove that your case to a place for your child outweighs the school’s case that they are full. It is not entirely true to say that transport can’t be used in this, as someone said downthread; if the child will be getting themselves to school, and it is too far to walk, but the bus would be prohibitively long, then the panel may take this into account. It probably wouldn’t be enough on its own, but appeal, you can use anything you feel is helpful - they won’t stop you saying ‘you’re not allowed to use that!’ - it’s about painting a picture of your child and how life would be if they are not at the school you want.