There are some excellent recent threads about restaurants if you do a search - many of the high-end Bund-style or western restaurants will be in and around Sanlitun. There's also a simple list in the wiki.

Finding a taxi is getting increasingly hard as so many people book them through DiDi. You can learn to use DiDi with minimal Chinese - there's a guide in the sticky at the top of the sub - it's even quicker if you do it via the wallet area in the wechat app. If you're worried about them calling there's a text message button in the app that says "Don't call, I'm at the pin".

Schools - I've been through 3 and they're all much the same. Most will give you a free trial lesson so you can find one with a teacher you like that fits with your location and lifestyle. I learnt faster in one-to-one classes than small groups, but everyone has different learning styles.

Clothing. There are malls everywhere. Sanlitun has a concentration of western chains. For work clothes it's very cheap to get trousers/shirts/suits tailored - search the subreddit for 'tailor' for recommendations. For cheap/larger clothes Decathlon has a wide selection.

Insurance depends on budget - there are probably some very cheap Chinese providers, but check what's actually covered as you'll probably want to use the international hospitals. I have Cigna who have been excellent.

VPN: Seems to depend on your area and internet provider somewhat, but China Unicom+Express works well for me when browsing/streaming. Setting up your own VPN with shadowsocks is another option. Astrill works very well for 'large downloads' but the customer service is embarrasingly bad.