General shots? Indoors? Outdoors? Not only does the intensity of the light change, so too does the colour balance. You'll probably want to set that on Auto WB most of the time.
Outdoors on a sunny day, set it to 200 iso. On a cloudy day, 800-1200 iso. Indoors, at least 800 iso. But if you are using a flash, you can easily work at 400 iso. Your camera has a flash sync speed of 1/500 sec - my pro level D5 only syncs at 1/250 - which is really good for using the camera outside to eliminate unwanted shadows. Like if the sun is coming in from behind or from one side. Pop a flash in the hot shoe and the high sync speed gives you more control to balance the light.
You also have to consider what you are shooting. If it is a moving object, you'll need a shorter shutter speed to freeze motion - at least 1/250 sec. To freeze sports action, I recommend at least 1/1000 sec. But if you are shooting static objects, you can opt for longer shutter speeds. Just be sure to support the camera properly. Get your left hand underneath the body and lens. Keep your elbows tucked in to your sides. If you can lean on something for further support, use it. Or consider buying a tripod, something useful for landscapes or shooting plants/flowers.
Your lens is a decent quality item with a useful range. Be aware that the camera's sensor is not what is referred to as a full-frame sensor. Full frame sensors are equal in size to slides or negatives in film cameras, which is 24mm x 35mm. Your sensor is 18mm x 24mm, exactly half in size.
It has an effect on lens lengths. It adds 50% to the length - so, 100mm on your camera would equal 150mm on a full frame body.
Your 18-55mm lens is equal in perspective to a 35-80mm lens on a full frame camera. You go from a slightly wide angle view to a moderate telephoto length. The wide views are great for social gatherings in getting group shots. The longest length is very good for doing a nice individual portrait.
Here's a review of your camera from Ken Rockwell, a smug little dingdong who runs a popular photography website.
www.
kenrockwell.com/nikon/d70.htm