What Simple Changes Made the Biggest Improvements to Your Delphi Programs [closed]

Question

.BeginUpdate;

.EndUpdate;

;)

Use a Delphi Profiling tool (Some here or here) and discover your own bottle necks. Optimizing the wrong bottlenecks is a waste of time. In other words, if you apply all of these suggestions here, but ignore the fact someone put a sleep(1000) (or similar) in some very important code is a waste of your time. Fix your actual bottlenecks first.

Stop using TStringList for everything.

TStringList is not a general purpose datastructure for effective storage and handling of everything from simple to complex types. Look for alternatives. I use Delphi Container and Algorithm Library (DeCAL, formerly known as SDL). Julians EZDSL should also be a good alternative.

Pre-allocating lists and arrays, rather than growing them with each iteration.

This has probably had the biggest impact for me in terms of speed.