Birth to 3 months of age 

Tummy time should be the highlight during this time
-Lift head off surface for short periods of time to visually explore environment 
-Turn head to the side and then rest it back on surface- each side equally ideally
-Baby may push up on arms when on belly
-Visually tracks moving toy from side to side while laying on back
-Keeps head centered to watch toy or faces while laying on back
-Able to move fists from closed to open
-Able to bring hands to or near mouth
-Moves arms and legs off surface when excited- when child is laying on belly and back

3 to 6 months of age

Rolling and sitting are the big motor milestones of this stage
-Rolls from back to belly and belly to back easily to change position
-Tolerates floor play for up to 30 minutes spending most of the time on belly
-Able to push up on straight arms when on belly and maintain for a few seconds with head lifted and in the middle
​-Able tor reach out for and engage with toys nearby when on belly
-Able to tolerate full weight on both legs when held up in the standing position
-Able to reach with both hands to play with feet when laying on back
-Able to transfer toys from one hand to the other when laying on back
-Able to maintain sitting position when placed there for a few seconds or more, using hands to support

6 to 9 months of age 

Independent movement is the main focus during this time.    
(Pro tip- this is the time to go through your house again and from a low crawling position to baby proof your home in preparation for your little one now curious and on the move)
-Sits independently and without suppport
-Reaches out and obtains toys when sitting and then returns to upright without loss of balance
-Able to rotate head to visually track objects when sitting without loss of balance 
-Transitions from belly or back up into sitting and also out of sitting to tummy or back
-Starts to move forward with alternating leg and arm movements when on belly
-Strong skills when on tummy to push up onto extended arms and reach out to grab toys, may push onto hands and knees
-Strong rolling skills and may use to move throughout space to obtain toys
-Tries to imitate others during simple play such as clapping

9 to 12 months of age 

Exploration is the highlight of this stage, smoothly moving in and out of various positions to explore environment and get toys.
-Smoothly transition from belly, back or sitting into quadruped (hands and knees) and maintain that position or transition back out of it
-Crawl on hands and knees with smooth and quick cross lateral pattern
-Pull into standing from the floor and side step along furniture or the wall
-Maintain standing at surfaces, when placed there and even without support for several seconds without unsteadiness
-Take independent steps 
-Throw objects when independently sitting without loss of balance 

12 to 18 months of age

Freedom of mobility is the highlight of this stage
-Independently walking and with a more linear, reciprocal patterned able to progress into a fast walk smoothly
-Stand up from the floor in the middle of the room without pulling up
-Squat down and grab a toy then return to standing and walking
-Lifting leg to kick or attempt to kick
-Transitions over various surfaces when walking without loss of balance

18 to 24 months of age 

Speed is the highlight of this stage
-Running and with smooth pattern
-Jumping with both feet leaving the ground
-Climbing on furniture and playground equipment
-Ascending and descending stairs using a reciprocal pattern, may still need support from rail or wall
-Stands on tiptoes for a few seconds
-Tries to imitate movement patterns
-Successful kicking of large ball