Myself, I like starting with low density suburbs-like city, then make a high-density NYC style further. I then like to arrange public transports, and finally play with the terrain to make some mountains villages, coastal city, etc. That's usually when I just spend more time following cars or trains around my city than playing.
Love this. I always turn on unlimited money and try to just build good looking areas. Sometimes I focus on suburbs and other times I try to make a good looking downtown. I love to make flashy coastal areas too.
I usually spend an hour adjusting the terrain before even starting a city. I don't like flat land! I'll make a mountain for rich assholes to live on, and make some kind of park on top that I'll spend awhile detailing, so my citizens can sit in a nice park and see a great view all around the city. I also like making a big nature reserve with lots of hiking trails and interesting things to see.
I always try and make my city as bike- and public transit-friendly as possible, I make footpaths and bike lane bridges across bodies of water that the cars have to drive around :). I like building universities too.
Oh and sometimes I'll make an entire city block private with only one house, surrounded by trees, with their own fountain and tennis court or something. I wait until a nice house pops up and then make it historical and let them enjoy their little paradise for awhile. And then I launch an asteroid on them. It makes me feel better about being poor in real life.
Oh man, I usually start off "small" with unlimited money and make suburbs, gradually to high density. Then at some point I'll be like "oh man I should build a great big urban center!" and realize how performance-taxing it is!
Most of the time I just roam around in my city and watch cars move by.
Oh I feel you haha, up until recently I've been using an i5 2500K, which showed a little bit of age. Since then I've upgraded to an i3 10100, so it should be a little bit better, but I haven't played Cities with it. I plan to upgrade to something like an 11400 or better for Cities 2 :)