Food
Eat little and often.
Have starchy carbs with every meal.
make sure you eat the brown version of carbs i.e. broen bread, brown pasta, brown rice.
Plenty of fruit and veg to snack on, don't limit these.
Go for low fat options where possible.
Have 2-3 portions of low fat dairy every day.
Eat low GI foods where possible.
Have treats every now and then.
Drink plenty of fluids.
Exercise
Avoid exercise that jars such as jogging in the 2nd trimester and take up cross training instead.
Go for plenty of walks.
Take up swimming or yoga.
Avoid sit-ups from the 2nd trimester onwards to protect your stomach muscles.
Avoid exercises that yo have to lie on your back to do
Don't exercise so much that you're so out of breath you cannot hold a conversation.
Take extra care when stretching.
If it feels uncomfortable then stop doing it.
Good luck!