I suggest your approach this project by considering what you care about most. What are your priorities? Make a list of these priorities, and choose the top 10. Then, list laws related to each of these priorities. For each of these laws, institute a punishment that you feel is fair.
I will give you an example. My pet cat is very important to me, so I place a priority on animals. I will institute a law against mistreating animals in any way. The punishment for hurting or killing an animal will be the same as doing so to a human.
Suppose I also created a democracy, but one based on public safety. I could have a law that states all those convicted of murder be put to death. I could do the same for sex offenders, and drug traffickers. In this case, my democracy centers around people's freedom from the tyranny of crime, as opposed to the freedom to do whatever you want.
My country will be a democracy. I want to start with a law that says that people cannot lie about candidates for office or or about political policies being promoted by a person or group. Anyone caught doing this would be either prevented from running for office for 5 years (if a candidate did it) or prevented from running ads (if it were a private citizen) for that same time period.
I would also make sure my justice system focused on making victims "whole" and so I would say that the penalty for theft is to repay the victim either monetarily or through doing work that will help them. That way victims would feel like the system actually cared about them.