Optimizing Code

In the link that SpLinux posted, most of those speed improvements will have little effect unless they are run thousands of times per game loop. Don't get me wrong, they are faster, but most of the time, it's a waste of YOUR time to use those optimisations. Only bother with them if you ARE performing them lots of times.
Tips that fall into that category are:
1, 2, 8, 11, 12, 13, 16, 17, 19

Some of the tips are actually wrong (at least in this day and age, they are), such as:
4: most new graphics cards handle 24 & 32 bit better than 16
9: Doesn't appear to be:

image = CreateImage(800, 600)
start = MilliSecs()
For n = 0 To 100000
	z = ImageHeight(image)
	For x = 1 To z
		y = Rand(0, 1)
	Next
Next
Print MilliSecs() - start
FreeImage image

image = CreateImage(800, 600)
start = MilliSecs()
For n = 0 To 100000
	For x = 1 To ImageHeight(image)
		y = Rand(0, 1)
	Next
Next
Print MilliSecs() - start
FreeImage image

WaitKey
End

14: No improvement noted. Try it yourself.
15: The first example is better. If the X=1 comparison fails, then the Y=1 comparison isn't even performed. In the second example, both comparisons are ALWAYS performed. Now which do you think is faster? The following code compares them (and tip 16 as well)

;Tip 15 Ex. 1
SeedRnd 1
start = MilliSecs()
For n=0 To 10000000
	x = Rand(0, 1)
	y = Rand(0, 1)
	If x = 1
		If y = 1
			x = Rand(0, 1)
		EndIf
	EndIf
Next
Print MilliSecs() - start

;Tip 15 Ex. 2
SeedRnd 1
start = MilliSecs()
For n = 0 To 10000000
	x = Rand(0, 1)
	y = Rand(0, 1)
	If x = 1 And y = 1
		x = Rand(0, 1)
	EndIf
Next
Print MilliSecs() - start

;Tip 16
SeedRnd 1
start = MilliSecs()
For n = 0 To 10000000
	x = Rand(0, 1)
	y = Rand(0, 1)
	If x + y = 2
		x = Rand(0, 1)
	EndIf
Next
Print MilliSecs() - start

WaitKey
End

18: Wheres the speed increase?

SeedRnd 1
start = MilliSecs()
For n = 0 To 10000000
	x = Rand(1, 3)
	If x = 1 Then y = Rand(100)
	If x = 2 Then y = Rand(100)
	If x = 3 Then y = Rand(100)
Next
Print MilliSecs() - start

SeedRnd 1
start = MilliSecs()
For n = 0 To 10000000
	x = Rand(1, 3)
	Select x
		Case 1
			y = Rand(100)
		Case 2
			y = Rand(100)
		Case 3
			y = Rand(100)
	End Select
Next
Print MilliSecs() - start

WaitKey
End

Some Tips ARE right on, such as:
3, 5, 7, 10

And some Tips include some misinformation like:
6: GetColor is slow, but SO IS READPIXEL! Don't use EITHER if you can avoid them.
20: Goto is FAST!. Why not use it? I mean, if you're looking for optimisations why would you throw it out? A few Goto's in the correct places are not going to cause you any bugs. That being said, this is an optimisation that is rarely needed and falls into the first category I listed above.

Someone should update that page...

In fact, this has motivated me to write my own (unfinished)Speed Tips page...