1. Decrease your guest list. This is often the quickest way to reduce cost without having to cut much of anything else. Go through your guest list and only invite those who you absolutely cannot imagine your day without. Or, remove plus ones from truly single guests who will know other people at the reception (except for wedding party members - I would recommend still giving single wedding party members a plus one).
2. Search for non-traditional wedding venues. A ballroom is likely to be more expensive than a museum, or historical library, or aquarium, or a local park, or a local restaurant, etc. Or, find a venue that allows you to bring your own caterer. Restaurant catering is often way cheaper than a wedding venue caterer.
3. Eliminate things such as favors. These are often left behind by guests anyway, and can save you hundreds of dollars if you skip them (depending on what you were planning to do and how many you needed).
Hi Courtney! A 40 person guest list is a great start!!
This WeddingWire article has great tips on how to shrink your budget: 9 Go-To Ways to Save Money on a Wedding, and you should also check out these discussions with input from lots of different couples: