The best area to stay is either in Lavington, Hurlingham, Kileleshwa and just commute into Westlands and CBD. CBD is too hectic normally. Airbnb over the hotels for value here. The Arbor in Lavington is my hidden sanctuary in Nairobi, decent Asian fusion food, but a beautiful garden and the most brilliant boutique. However if you want one stop shopping, go to Spinner's Web. The Masai Market moves every day, but you can get the low down and prices here.
Get a SafariCom data card for less than $10 so you're not lost, and sometimes is more reliable than wifi. Uber is very easy to use, but usually Taxify is better. Half the time the roads don't work and often times traffic can be very facetious. There's no rhyme or reason why or where it may be particularly bad. However, as a rule traffic is bad after a hard rain and after pay day (3rd week of the month).
Kenyan food is quite bland, but there are quite a few other cuisines that you can try out! For example Habesha is a wonderful Ethiopian place where eating with your hands off a giant plate. That doesn't mean there are not wonderful boujee places to have brunch. The easiest place for meetings and lunches are the many Java Houses that freckle every major shopping center.
Boujee-iest Places to Eat
Beit e Selam: Gorgeous garden, poor service, but all the dishes are very good, my top pick for vistors! make a res!
Ate: wonderful enviroment, wonderful flavors
Chez Sonia: great wines, meh food, good places to chill on sunday afternoons
Amani Ya Juu: Closer to town (in Westlands), basic food but lots of families on weekends. This this a social enterprise that supports refugee women and in general their design and quality is much better!
Garden Restaurants in Karen
Best Chinese Restaurants
Places to AVOID (both to order and to go to): 7 Day Chinese, For You, Mister Wok, Panda, The Graceful Chinese Restaurant, New Overseas Chinese and Korean Restaurant, Lotos, Spring Garden, China Plate
Places that are not great, but okay: Eastern Garden Chinese, Double Dragon, Jingling
Obviously Nairobi is the set off for many safari's, but if you are not going on safari, there's plenty of animals in the city. Giraffe Manor is very picturesque but honestly, meh. If you don't want to dish out the cash, go to the Giraffe Center right next door, where you can feed the giraffes and spend as much time with them as you want. The baby elephants at the Sheffield Elephant Orphanage are fed 11am-12 pm everyday which is also when you can visit. However if you play another $50 you can foster an elephant have have one on the one time.
If you're looking to volunteer, try the Kibera Girl's Soccer Academy, featured in Slum Survivors, and a Ashoka Changemakers school. Kibera is an experience in and of itself.
Places to Go Outside of Nairobi
Better to rent a car and drive yourself!
The Masai Mara: Nuff Said. You can
The Boat House: Drive out to Mt. Kenya Safari Club and spend the day feeding ostriches, and hanging out with endangered bongos! If you get tired, go get an overpriced (but delicious) drink at the Fairmont next door. The minimum is 2000 KSH/pax but the hedge maze, sprawling vistas, and croquet are more than worth the price. On the way back to Nairobi, have lunch at Trout Tree!
Brandy Bus: Even this place is only in Karen, it really feels like world a world away. It has all the modern amenities, and even the shower is really great. The two bedrooms upstairs fits 3 people, and the you can fit another 2 downstairs but it less comfortable than the bed.
The Kenyan Coast
Diani: Don't worry about staying on the beach, it's a quick walk away. Stray away from the normal watering hole, 40 Thieves, so that you can go kitesurfing. Diani Blue and Nomad is the best place to hang out during the day because they have amazing swahili curry and cheap wine. Almanara has incredible ice cream. If you have a big group get a house in Diani.