Enjoy sex whilst you're still slim, during the third trimester you will feel as unsexy as it gets. Pregnancy is gross.
It's normal not to have a bump until 25 weeks and then all of a sudden be huge.
After 25 weeks when you start feeling movements pregnancy becomes more enjoyable (for me it did anyway).
Just because you've reached 12 weeks doesn't meant automatically you'll feel instantly better. It can go on a while longer but try and perceiver.
Midwife appointments are a bit of an anticlimax I found. I got excited for my first few and then they just do urine, blood pressure ect where as I thought I would get actual pregnancy advice. Don't be surprised if they don't listen to the heartbeat ever either, mine never have.
Eat what you like and don't let anyone judge you for it. I could only keep down lucozade for weeks and everyone kept telling me how awful I was for it.
The best advice is never take anybody's advice.
Don't tell people or buy things straight away if you can help it, it makes it a really long pregnancy.
Keep a pregnancy diary to look back on!
Your body temperature will go up loads as you are basically a human incubator.
If you have to have a GTT test it will make you feel a bit poorly sometimes after the drink but nobody ever admits to it.
Maternity clothes are mostly navy blue, stripy and hideous! Wear all your favourite clothes one last time whilst you fit!
Congratulations! 
