A checklist is always a good place to start your event. My events are only ever as good as the tedious to-do lists I make for them (and if they're really special, they get a whole binder!) A good checklist is going to cover all your basics - setting the scope and feel of your event, setting up a budget (templates for that coming soon!), and getting speakers or other key people lined up, before all the other details.
This checklist doesn't give very specific dates because you know your event better than I do - some events can be pulled together in a matter of weeks and other needs months and years to plan.
One of the most important parts of this checklist is the day-of part. Whether you are hosting a backyard baby shower or a major conference, you need to have a day-of plan and contingencies for things going wrong. Vendors can show up late, guests can arrive awkwardly early - think through how you will respond. You can't be everywhere at once. Delegation will save you. Think through the people that are going to be your crack team and delegate as much of the day-of details to them as you can.
Without further ado - here is an event planning checklist. Special note: this is not a wedding checklist (that will come later!)