When preparing for a party, (IMHO), this is the first thing you/we need to accomplish, finalize and settle above anything else. Though I know, during this time, you have already a theme (may be themes) in mind for your event. It's better if you have a clearer picture of how you visualize your party because it will help you deciding which venue suits your theme.
Anyways, I'd like to share to you what are the criteria I have when preparing our own party.
1. I ask myself first, how many guests (a rough estimate) will attend our party? I even ask my husband regarding this!
2. If we have a rough estimate, I ask myself and him our budget for the venue.
(In our case with Jacob's 1st Birthday - he gave me the total budget he will give me for the party (excluding my personal expense for whatever "arte" I wanted :)). I set aside around 10k-15k for the venue, however, I find out while searching the web about Prestige Tower (some details here) - that they will cover the venue in exchange of availing their minimum amount for catering catering service, isn't it a great deal? So, the budget I alloted for the party turned out to be part of other thing s I wanted for Jacob's party. )
3. If you have lots of options for venues, sub-classify it to:
a. accessibility - from where all/most of your guests will be coming from?
b. will there be a public transport in case some of the guest do not have a private vehicle?
c. time and date of your party (IMHO, I think, as a DIY Party Planner, you should stick as much as possible to the time and date you wanted).
Personal kwento: With Jacob's 1st birthday party (again), I wanted it to be on Saturday, but since I really wanted Prestige Tower (considering above criteria) I settle for Sunday but on the time I wanted (which was 4-7pm). Luckily, I reserved/booked the venue ahead (5-6 months before the event date). Always ask for a clear contract copy (read and read and read.. then ask ask ask [if you have any concern]). Do not hesitate to ask and tell them what you really wanted for the party.
4. If you have time, do an Ocular Inspection. But before that, make a list of questions and details of your party. You don't want to miss anything for your party, right? I always do this!
5. If you are already satisfied and final with the venue, settle the reservation fee.
6. A week or 2 weeks before the event, remind them about your party. Also, if you have a ny revisions, additional requirements, advise them ahead.. If you're only communicating through phone, do not forget to ask who are you talking to (in case a problem may arise) and note it.
Will try to come up with a List of Party Venues that will surely help you preparing for your own event.