No matter your skill level or age there is a hiking trail for you.  Some suggestions are:

Piestewa (Squaw) Peak

Moderate: 2 Miles/3.2 km, 1-3 Hours, Family Friendly

Hikers, walkers, sightseers and runners alike flock to this prominent peak like moths to a flame, drawn here in part because of it proximity to the city of Phoenix. Despite the crowds this mountain can still be a lot of fun, offering as it does a short but taxing 1,100 ft climb and many great views along the 1 mile route.

Camelback Mountain

Difficult: 2.2 Miles/3.5 km, 1-3 Hours, Family Friendly

Distinctive and dominant on the Phoenix landscape, Camelback Mountain is just begging to be conquered. The two different routes to the 2,680ft summit offer different challenges, and both are featured in this guide.  Echo Canyon is the popular route, which ascends 1,400 foot up the western side of the mountain in just over a mile. The journey quickly becomes a real leg-burner but delivers some good hiking experiences and a varied terrain.  The Cholla trail heads up a well maintained trail on Camelback's east flank, but becomes a challenging and technical ascent upon reaching the ridgeline. This fun 1.3 mile route becomes increasingly rocky and precipitous, and though the conditions here are not extreme, we'd certainly urge caution and wouldn't recommend this route for young children or folk with a strong aversion to heights.

Tom’s Thumb, North Side

Moderate: 3.7 Miles/6 km, 1-3 Hours

The trail is very well manicured, and will be nice hiking except for some steep elevation gains. Following the Tom's Thumb Trail you pass many other trails that go off to climbing areas that I saw several people using so consider those as well if you like to climb. You can also climb Tom's Thumb itself when you get to the top.

Pinnacle Peak

Easy: 3.7  Miles/6 km, 1-3 Hours

Pinnacle Peak is about 3.7 miles long and located near Desert Highlands, Arizona. The trail is great for hiking or running and normally takes 1-3 hours. It's the type of hike that can give you a good workout without being overly stressful or difficult. The problem is that everyone knows this so the trail can be rather crowded. With the very well maintained surface this is also a popular hike for runners so be aware that you may need to do some dodging from time to time.