Max tips and useful objects (thanks to Phil Acimovic)
pack & unpack - sends multiple streams of data through a gate or inlet, saves space and extra patch cords
scale - takes the input from a source like an Arduino and scales it appropriately for the desination (0-1023 could become 500-1000ms for a metro object)
loadbang - sends a bang when you open the patch: acts like a preset for your program (i.e. begins a process, loads a setting, loads a list, sets a level)
send & receive - transmits data across patches (even between subpatches) without using patch cords
pcontrol - remote control for opening patcher windows, great for visual feedback during a piece
onebang - allows only one bang to pass through left inlet, has to be reset by right inlet, gives a great deal of control when streams of continuous data are coming into your patch
line - creates smooth transition between levels (e.g. 0-80 on a volume knob in reason over 10 seconds)
random, decide, drunk, urn - random number generators, each with its own twist
key - each key on the computer
keyboard can be recognized in Max, can be useful as an alternative trigger
such as an emergency all-notes-off, flush, volume fade, etc.
Other Max tips
Watch your ints and floats, make sure decimal points are in every object carrying a floating-point number
Make "monitors" for yourself
Add extra number boxes, bangs, level meters, sliders, etc. to confirm that messages are getting through and so you can monitor levels. This will save you loads of time when trying to track down problems areas inside a patch.
Create your own objects
In larger, more complex patches it is often useful to isolate a section of the patch within its own object (with inlets and outlets as needed) to save space and reduce frustration.
Do your MIDI Setup first, and
use port letters (a, b, etc.)
In MIDI Setup, enter abbreviations for your standard inputs and outputs and then use those abbreviations in all of your controller and midi objects. Do this before you load your patch. These must be reset if your patch is used on a different computer.
Learn the objects
Take time to explore the object database. When you Option+Click an object and view the help menu, and Max shows you a number of related objects, check these out. They often save time or offer slight variations for your patch that will make a big difference.
Pretty isn't always best
Don't spend hours making your segmented patch chords look snazzy! It's not worth it. (But straight is often nice.)