We need to accept that being a politician is a job, and it needs to be treated like a job. That means, at the very least, a position description for each and every role (backbenchers, ministers, etc), and measurable KPIs. No second jobs, unless it is someone who has to put in so many hours per year to maintain a registration (e.g. health professionals). Even then, it would need to be limited to the mandatory number of hours required by the registration body.
Speaking of hours, there needs to be metrics measuring that people are actually putting in the time - including surgeries in their local constituencies. Failure to do so results first in docked wages, with escalating consequences for repeat offenders. Doesn't matter if you are a backbencher, whose party is not in government. Firstly, all non-ministers should submit a program of activities/research/projects to be undertaken (and to be approved as appropriate for their role). Then they have to actually deliver and report (like people do in "real" jobs). No free rides.
No employing family and friends (Australia bans this). In fact, staff in constituencies should be hired and overseen as part of the civil service. Definitely no donations, perks, etc.
No subsidised restaurants, and alcohol should be banned on the premises. Random drug and alcohol testing. Absolutely nil donations to political parties (including from themselves). Instead, a set re-election allowance for each seat being contested. Speaking of which, all people contesting a seat should have to undergo some form of security check before they can even stand for election.
Being banned for 10 years from taking up positions in industries related to portfolios/shadow portfolios held, while in office. Mandatory training in areas relating to any portfolios assumed, to ensure they are capable of making informed decisions.
And no more multiple holidays throughout the year. They get a set allocation of annual leave, and that is it. No extended parliamentary recesses. Mandatory attendance at a set percentage of Question Times, and parliamentary voting, unless they have verifiable reasons not to (e.g. sick leave, etc)
I am sure I can think of more, but that is a starting point. I am then happy to pay them a lot more, but only because they are then justifying their existence.