Walk and Run- To run, simply press forward. Be careful when
running, because Lara can run right off ledges. To make sure Lara
doesn't become suicidal, hold the WALK (SHIFT by default) button
down when approaching ledges.
Jump- To jump, push the JUMP (ALT by default) button,
and Lara will jump straight up in the air. To jump in a
certain direction, push JUMP and quickly push the desired
direction. To do a running jump, which can go greater distances,
walk up to the edge
, push
back, then push forward immediately followed by JUMP. To catch a
ledge in mid air, hold the ACTION (CTRL by default) button. Lara
can also jump and turn around in mid air. Do a backward or
forward jump, and push the '5' key on the number pad immediately,
and Lara will end up facing the opposite direction. This is
useful for jumping over enemies and still being able to target
them.
Actions- The ACTION (CTRL by default) button has many uses. It fires guns, pulls switches, uses keys, gets items, and grabs ledges.
Roll- To roll, simply push the ROLL ('5' on number
keypad, or ENDin water or during a forawd or by default) button.
Roll turns you around, and it can be used backward jump..
Jump Combo- Sometimes Lara will be able to use slanted
surfaces to her advantage. By jumping onto one of these, hold the
jump button and Lara will keep jumping. These are used to get to
higher places that Lara can't get to with a regular jump. 
Safety Drop- If a drop is high enough to do damage to Lara,
you may be able to perform a safety drop. To do this, Back up to
the edge using the WALK button. Press back, and quickly press
ACTION. Lara will jump back and grab the ledge on the way down.
Then let go of ACTION, and Lara will drop safely to the ground.
To shimmey, push right or left.
Climbing (TR2 only)- Sometimes Lara can climb ladders or gates. To
climb, go up to the ladder and press ACTION. Then press up, down,
left, or right to move in that direction. A speedy way to go down
ladders is to let go of ACTION and then press it again right
after.
Swimming - To swim, jump into water, or do a swan dive
(WALK + FORWARD + JUMP). Use JUMP plus the arrow keys to move
around, ACTION to pull switches or get items, and ACTION against
a ledge to pull you out.
Blocks- To pull or push a moveable block, move Lara
against it, and push ACTION until Lara is in a slight squatting
position. Then push forward or backward. If Lara remains still,
this means that the block cannot be moved in this direction.