3rd birthday party: please share your tips

[skankingpiglet]

I'm starting to plan and book DD1's 3rd birthday party. I already have a bit of knowledge of dos and don'ts but I'm nervous I'm going to commit some awful error and I'm not sure of some of the etiquette.

I'm thinking of booking the village hall and mini softplay with bouncy castle, party 1-3pm, party tea of beige and sugar with obligatory bowl of crudités, cake in a character theme of DD's choosing, balloons. I'll book the hall for an extra 1.5hrs either side of the party to set/clean up. That's the bones of it I think?
I've been caught out with food/no food for adults/kids, most noticeably the party over lunchtime that only included a buffet of various Haribo followed by cake, and at the other end a party that had a full sit-down separate buffet for the adults, so I'll include a note on the invites that a party tea will be provided for the kids.
It'll be friends from her preschool, with a few from other playgroups and friend's children.

However:
-Invites. How many weeks before should I send out the invites? I don't want it to be so far in advance people forget about it, nor so late most people already have plans.
-Party bags. I'm well aware we'll have a number of shows who didn't RSVP. I want to do bags that aren't entirely pound shop crap (although realise the kids like a bit of tat), so how do I calculate how many to make up? I don't want to waste money making up a ton of spares that aren't used, but obviously the other end of the scale is even worse! Any good suggestions of what to put in that's inexpensive but doesn't break within 2 minutes?
-With the softplay are party games necessary?

Have I missed anything helpful/crucial/obvious?

I know I'm massively over-thinking this, and I've thrown numerous successful grown-up parties, but want to get it right so DD1 has a good time as she's been banging on about her party for months already (we didn't tell her she'd have one, she's assumed based on her friends having had them. She talks most days about it, it's a huge deal to her ). I also don't want a room of small children bored of the shit party! My usual tactic of supplying copious amounts of alcohol won't help me this time.

[CaipirinhasAllRound]

We're doing a 3rd bday party in a fortnight. Have bought 20 books from the works online as if you buy 10 they're £1 each. Reckon we'll end up with about 15 kids but we don't have any if the books so can keep the spares. Just doing a book and piece of cake for them to take home.
We're going to a small soft play place so no entertainment needed

[archersfan22]

I had a very different sort of 3rd birthday party, very low key at home, but the thing the kids liked the most (apart from general racing around together and pass the parcel) was the cake fountains - sort of sparklers that you put on top of the cake. The kids (ranged from baby to 4 years) were all spellbound watching them.
I wouldn't put them on the main cake as there tends to be a bit of ash residue, I put them on a separate offcut from the cake I'd used to make the main cake - you could use plain cupcakes instead. And obviously take sensible precautions eg there are no paper napkins etc nearby, all kids are safely at a distance, etc.
I put quite a bit of craft stuff in the party bags - eg buy a big pack of colouring pens and put a few in each bag. Then you can easily use any surplus at home. Pound shops and The Works are your friend for that!

[archersfan22]

Ps I'm sure you've thought of this but try to get the kids to run round the softplay/bouncy castle before the food rather than after to avoid any of them stuffing themselves and throwing up all over the equipment...