Tips from Kama Linden
Squats
  When performing a Squat (utkatasana) always bend in the hip and knee, never "bend your back" (always keep neutral spine)....never "bring your knees together"...the knee should be aligned right over the 2nd/3rd toe and under the hip joint. Pretend you are at a restaurant and someone is pulling the chair out for you.
Warrior 1
  Make sure your "core" (neutral spine, square hips) is your priority. Place your back foot where it is a) in a comfortable "turn out" and b) on the ground. Never worry about making a "90 degree angle" with your back foot or "crossing it behind the front heel"...always honor your hips.
Warrior 2
  Don't worry about being "flat"...the world is round....both hips should not have to forcefully "face side", and neither should the shoulders. Use a mirror in front of you to make sure your knee is aligned over the front toe, the hip has a "break" and both hips and shoulders are even (not popping through the joint) and use the side mirror to see how "pretty" the pose looks when you are not forcing your joints!
Parvrtta Trikonasana
  NEVER TURN IN YOUR SPINE....use an appropriate block or prop for the inside hand. Bend at the hip joint, keep both leges straight, both sides of the waist long, and mind that shoulder...never merely "bring your top arm to the ceiling" make sure it is not popping out of joint....always hold the arms in the frame!
Knees Chest Chin/Chatarunga Dandasana
  I merely do a bent knee pushup with the spine in neutral alignment. Sticking your Butt out will eventually hurt your back, and will not teach you to use your triceps needed to do the full CHATARUNGA DANDASANA. Also, NEVER PUT YOUR FACE ON THE FLOOR during any pushup! Always keep the PLANK ALIGNMENT and merely bend your arms. Dropping the head not only risks hurting your head/face, but it causes direct tension in the shoulders. In the Straight version, never try to SWAN DIVE...again, putting extra pressure on the shoulders and sticking your butt out will not make you strong and can hurt your shoulders and back.
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