Closed cell foam pad is really nice - I saved a bunch of 1/8" padding that something shipped in (probably the table itself hah) and I glue it on in big spaces, or use it to wrap around things that I strap on to molle panels.
For temporary fixes, I cram microfiber rags in spots. Works in a pinch until I can get in and properly fix whatever it is. I carry a handful around - nice to have to have around the vehicle in general for all sorts of things.
Make sure all the nuts and bolts are tight.
If you need to add spacers or washers - sometimes that's needed. Rubber washers can help some too.
Make sure the table closes tight. May need to adjust or add some padding/washers to whatever the closing mechanism is.
For very small gaps - silicon grease (clear, but does eventually dry out) or lithium grease (white, but stays pretty much forever). Don't use lithium anywhere where you may contact it - it will rub off and can stain clothes. Silicone grease though it pretty safe and will wash off, but it can still make a mess.
On my Turn Offroad one - the latching buttons kept coming loose and rattling. They were nice, but wouldn't stay tight. I eventually ditched them and just went to a bolt with a wingnut and rubber washer.