Manage my money better

I go through phases of writing things down (money-wise) and then I get frustrated. I can manage other people’s money just fine (work) but not my own. How does that work?

I never know when bills are due or when billing cycles are. I have to get on this, including paying my bills on time (I don’t even have that many!) and know when my billing and statement cycles are. Maybe I should get a big calendar and post it on the wall? Write a budget for six months at a time?