The first thing I would do is increase the personal tax free allowance to around £20,000 or more, maybe link it to minimum wage x 30-35 hours.
Then I would amalgamate income tax and NI to make the system easier, so abolish NI but add the necessary % to income tax. I would get rid of employer's NI completely to boost the job market but put a couple of % on Corporation Tax.
I would also force a better balance between staff pay at different levels and incentivise more profit sharing schemes to make things fairer and reduce the inflated earnings of wealthy business owners.
Obviously to balance the books I would need to make huge cuts in spending but these would include abolishing a lot of tax credits for low earners as people should earn their own money. Means test all remaining benefits including the state pension and increase ongoing financial checks to cut down on benefit fraud. It shouldn't be an easy option to live on benefits. This would all need to be carefully planned to avoid critical cliff edges and allow people to earn a small sporadic income for a lower level of benefits to account for those trying to top up their income from self employment. Back in the 1980s, there was a weekly enterprise allowance (of limited duration) for the newly self employed to help them get started - something like this should be brought back to encourage people such as the out of work, the disabled and stay at home parents of young children to earn what they can working from home, etc.
Scrap the NHS and set up a European style (not US) insurance contribution based system. Introduce ID cards and ensure only those over 18 who have paid in (or are genuine emergencies) are treated unless they can pay the bill. The current free-for-all needs to stop. All health services should remain free for under 18s if they have British citizenship - everyone else needs insurance or to be entitled to contribution-based state pension based on years worked. We have an aging population so can't possibly pay for everyone in the future. Those that can afford it should be incentivised to go private by offering tax relief on private health insurance. I really don't care if it produces a two-tier system, there needs to be a safety net, but not to the extent that exists now.
Set up many more minor injury units/24 hour GPs in the community to remove the pressure on A&E which should be restricted to real life-threatening A&Es (or those referred from minor injury/GP) only. Also set up more separate mental health and addiction units as these issues need to be dealt with away from A&E. GPs need to invest in more equipment to reduce the need for hospital visits. Things like blood test analysis, ECGs and scans should be available at GP surgeries (they are in many other countries) to speed up the system of diagnosis and treatment.
Re-organise local councils to remove the postcode lottery that occurs in many aspects of local council services and standardise everything across the regions which would simplify the rules, and cut the need for so many staff. The ridiculous planning system needs a complete overhaul as do many other local services.
We should incentivise multi-generational living, not penalise people for building annexes on their homes. We should offer more tax incentives for carers of all types, whether it is care of young children or the elderly. An increase in the tax free allowance should be provided for anyone who has a dependant relative (child or elderly relative) living with them. We need to get away from the need for two full-time working parents - it is detrimental to parents and children alike and is increasing the need for social care. The Government currently pays for third-party organised childcare, but offers no incentive for families to look after their own children and I find that very wrong. Surely in most cases, the best care is given by a parent or close relative. Whilst I wouldn't want to see a return of the 1950s style housewife, I think in the early years should be made easier for either parent to reduce hours, or take time off work to look after their children.
Council Tax should also be abolished. Paying for things like education and social services on the basis of the value of your house (in 1991) is a crazy idea. Also, the fact that it is a local tax means that there are huge discrepancies across the country with Londoners paying much less than everyone else. Everyone needs to contribute and again I would prefer that these taxes were added to income tax. I do however approve of the new £2m mansion tax and think that is a better solution to shift some of the tax burden to the very wealthy. I also think an annual house tax like this would be preferable to the current system of stamp duty (which I also think should be abolished).
Services such as bin emptying should be on a much fairer 'per bin' basis. Road repairs should be paid for from fuel duties (including duties on electric car usage) so they are paid for by those that use them most - ie. per mile. Road tax is another whole unnecessary department that could be scrapped if we just put a higher tax on fuels.
Education is another problem area, but I could make a whole other long post about that so I won't go into it here as this post is already long enough!
I think we also need to substantially increase import taxes, including import taxes on food. We need to support British farmers and eat more local produce. Food flown round the world should be an expensive luxury, not a cheap alternative.
I believe that if taxes and benefits were much more transparent, people would have less issues paying them!