What are some ways to keep biking when you have a car?
I guess you have two main tasks, and they involve preparing your &quot;internal&quot; (psychic, mostly) environment, and you external (domestic, mostly) environment.
About internal environment:

You have to convince yourself, or keep convinced, that you actually LIKE TO, WANT TO and SHOULD ride your bike;
You should think AND feel AND know that riding a lot is wiser than driving a lot. There are innumerable hard facts to support this point of view;
You have to look suspiciously to your car all the time. It is a temptation, and should be a last resort since it is all the time tempting you to succumb so that it can do its harm (this is somewhat metaphorical, but somewhat literal, too).
Resist any eventual harassment from family, friends and neigbours in favor of the so-called car culture. Watch these videos, they are awesome, and can help YOU to &quot;harass&quot; car-cultists!

About external environment:

Biking should be simple, not complicated. Leave your bike close to the exit, and your car keys far away from it. Keep your bike-related belongings close to the bike, and the bike always ready to be ridden.
Don't depend on special preparations for riding. Use fenders, &quot;sofa&quot; saddle and platform pedals if necessary, so that you can use regular clothes.
Have more than one bike if this will make you ride more, even if one of the bikes is just for errands.
Keep fit. The more you ride, the easier it is to take one more ride. The less you ride, the harder it is to be back in the saddle again after a &quot;long&quot; time.
When making long term decisions about your house, your work, and your new purchases, your habits, your schedules, etc., avoid the ones that will put you closer to your car and/or further from your bike.

I guess all this is essentially personal and subjective, but I think this is the general way to handle this issue.
Hope this helps