The problem is the size of the districts. With 475k people in each Assembly district and 950k people in each Senate district, it should be no surprise that candidates require lots of money to win — that’s a lot of people to meet, yard signs to put up, mailers to send out, and tv eyeballs to reach. Additionally, it should come as no surprise that lobbyists and special interest groups hold so much power because, in addition to having access to lots of money, these groups are capable of mobilizing a mass of volunteers to knock on all those doors and help candidates cover such an immense territory.

If we want to talk about real reform then we must talk about the number of districts we have. California has had an 80 Assembly/40 Senate apportionment since 1854, in spite of the fact that the population has grown by nearly 37million since that time nothing has changed. Not only is the size of current Assembly district nearly 4-times greater than the entire state population of California in 1854, the average Assembly district is also 3-times greater than that of the second largest lower State house (Texas comes in second at 160k to a House district, while New Hampshire is last at just over 3000 people per House seat).
http://www.ncsl.org/programs/legismgt/elect/cnstprst.htm

To break the power and undue influence that special interests have over our Legislature we must create more districts; there by lessening the need for these massive campaign war chests and volunteer armies, allowing the Legislator to spend all the new found time not spend at fundraisers as advocate for their district.