Warrior 1 increases the flexibility of your hip flexors (front of your hips). Keeping the hips square can be a challenge if your hips flexors are tense. If this is your case, instead of sacrificing the position of your front knee or your rear foot, shorten your stance.
If your hips are flexible and you would like more challenge, increase your stance and sink the hips down. This will make your quadriceps work harder.
* A great way to get into Warrior 1 is to link it with Downward Facing Dog. If you would like to start from this asana, scroll down for the instructions, and then come back here for the rest of the steps.
Look straight forward or look up at your hands. But keep your neck long. Try not to compress the vertebras in your neck.
Clasp the hands together, above your head. This will give you more leverage to pull up and lengthen the spine, which feels very good. This variation can also help to open up your shoulders. If they are tight, pressing the hands back gently will help to increase their flexibility.