Dining in a restaurant with kids can be very enervating and embarrasing. Not only that you have to desperately try and keep your wiggling toddler seated and silent, you also have to manage the disapproving looks from other (non-parent) guests.
The root problem here is again boredom. So before you decide to eat out, observe your child's mood. If it's having a bad day and is getting on your nerves already, better cancel the whole thing. It wouldn't be worth it anyway.
Consider an expedition to the jungles of Africa. Would you go with just picking your jacket and car keys? This is something similar, going out with kids requires preparation.
Bringing toys is generally a good idea. Some "family-friendly" restaurants supply toys, but you don't know what they've been through already, so having your own stuff gives you some of a security if you're very concerned with hygiene.
Since the "playground" in a restaurant is rather limited, avoid bringing toys that require mobility, like remote-controlled cars or balls. Coloring books, crayons and paper, story books or dolls / action figures can also be used while seated. But be careful with pencils and especially crayons, they require a certain amount of observation, otherwise you end up with eaten painting equipment and modern art on the white tablecloth.
It can also be a good idea to buy some cheap toys and prepare a "surprise bag". That will keep the child excited - they learn the connection between "restaurant" and "new toys" astonishingly quickly. And you can connect the gift with some blackmailing if you threaten to withhold the bag in case of bad behaviour.
Going to a restaurant should be something special. Making it an event for both you and your child keeps the latter excited and interested. So also don't insist too much when older children show resistance to go out. If they absolutely don't want to, don't force them. That'll spare you some nasty experiences.
If it's not McDonald's where you're going, make sure to have a table reserved. Especially on crowded days it's a good idea to be early so you don't have to wait for your food too long.
In case your child is choosy with food, better bring some of his/her favourite so you can provide at least a snack if the ordered meal is not accepted. Whatever comes, as much as possible make it a joyful experience. A spilled water or some scattered food won't hurt anyone, so take it easy. It's just a kid!
