How to save log?

My AppleScript needs to save to txt-file log few times a day some data. What is best way to do this?

This is some code I used to log errors in a batch process. I deleted out all the specific stuff so you can see the basic outline. You should be able to pull what you need from here:

global TotalCount
global TotalNotProcessed
global ErrorLogFile
global FileVersion

tell application "Finder"
	activate
	set chosenFolder to (choose folder with prompt "Process all files in what folder??")
	set TotalCount to 0
	set TotalNotProcessed to 0
	set FileVersion to "_1"
	set VerNum to 1
	repeat while (exists file ("ErrorLog.log" & FileVersion))
		set VerNum to VerNum + 1
		set FileVersion to ("_" & VerNum)
	end repeat
	set ErrorLogFile to (make new file at desktop with properties {name:("ErrorLog.log" & FileVersion)})
	set ErrorLogFile to ErrorLogFile as text
	
	my folderprocess(chosenFolder)
	
	activate
	display dialog ("Total files processed: " & TotalCount & return & "Number of errors: " & TotalNotProcessed) buttons "OK" default button "OK" giving up after (3 * days)
end tell

on folderprocess(chosenFolder)
       --repeat to go through all the files in the folder
	try
		--Do some stuff. I deleted all my specific code to give you the basic log file part
	on error
		set TotalNotProcessed to TotalNotProcessed + 1
		display dialog ("Error") buttons " " giving up after 3
		try
			set the OpenFile to open for access file ErrorLogFile with write permission
			write ("ERROR" & return) to the OpenFile starting at eof
			close access file ErrorLogFile
		on error
			try
				close access file ErrorLogFile
				set the OpenFile to open for access file ErrorLogFile with write permission
				write ("ERROR" & return) to the OpenFile starting at eof
				close access file ErrorLogFile
			on error
				try
					close access file ErrorLogFile
					display dialog ("Problem writing error log! Log may not be accurate!") buttons " " giving up after 5
				end try
			end try
		end try
	end try
	set TotalCount to TotalCount + 1
	--end repeat
end folderprocess