To raise/lift one´s leg
I´m trying to understand the differences between the verbs “to lift” and “to raise”. I know that in some situations we can only use one of these words (e.g. “to raise one´s hand to ask a question”, or “a crane lifts the load”). But in some cases I´m not sure about their usage, e.g.:
1) “RAISE your leg!” – to say to a child to put on its shoe.
2) “RAISE you leg like a flamingo does”.
3) “LIFT your leg high! Higher! Even higher!” - if I see that a person makes efforts, but it results not to be that easy to lift his/her leg.
Can I use them in the following situations? As far as understand, if we use “to lift”, it means that the physical effort is implied.
Thank you for your invaluable help!

Question

To raise/lift one´s leg
I´m trying to understand the differences between the verbs “to lift” and “to raise”. I know that in some situations we can only use one of these words (e.g. “to raise one´s hand  to ask a question”, or “a crane lifts the load”). But in some cases I´m not sure about their usage, e.g.:
1)	“RAISE your leg!” – to say to a child to put on its shoe.
2)	“RAISE you leg like a flamingo does”.
3)	“LIFT your leg high! Higher! Even higher!” - if I see that a person makes efforts, but it results not to be that easy to lift his/her leg.
Can I use them in the following situations? As far as understand, if we use “to lift”, it means that the physical effort is implied.
Thank you for your invaluable help!

Answer

If we are speaking about one's leg, these two verbs have the same meaning and would result in a person doing the same thing. 
There's a slight difference in the way we use it though: 
raise= normally used to describe an action you do to yourself. eg. I raised my arm.. He raised his leg
lift = normally used to describe an action you do to something/someone else. eg. I lifted the box.. I lifted his arm

Generally, we could say: "I lifted my arm" or "I raised my arm" and it has the same meaning, but we would not say "I raised his arm" or "I raised the box"

I would agree with your understanding here: " As far as understand, if we use “to lift”, it means that the physical effort is implied."

Hope this helps!

Answer

You put your hand up to ask a question.
"Lift your leg up (please)", would be how you would ask the child.
Lift your leg like a flamingo.
Raise is not what you would say speaking to someone. In written instructions you might see it.

Answer

It's an interesting question.  From my experience, I think that "raise" and "lift" are very close synonyms and are often interchangeable.

"Raise" emphasises that the action produces a vertical movement 
e.g. The crane raised the shipwreck from the sea-bed. (Lift OK but less natural).

"Lift" emphasises removal from a surface 
e.g. Can you help me lift that heavy box and put it over there?

Raise / lift your leg are both equally natural for me.
The party lifted / raised my spirits, and I feel happier now.

Raise feels a little more formal and in my experience is less common that lift.