All the things that I have learned so far and are not overobvious (Well to me anyway ;-).

Sliding radar

Sliding radar means your ship always stays in the center of the radar so you can see directly where you are. It's hidden somewhere in the MENU->CONFIG-panel of your client.

You can easily swap between different modifiersettings by pressing 1, 2, 3 or 4, but you first have to program the modifierbanks. Just open .xpilotrc or xpilot.ini in your favorite texteditor.
Instructions for .xpilotrc :

Find this line,
 xpilot.modifierBank1:
And change it (for example) into
 xpilot.modifierBank1:           CB3LB
If you couldn't find the line, just add it.
Next time you press 1 you will get weak clustermines and blinding lasers.
And the story for 2, 3 and 4 goes the same.

Instructions for xpilot.ini :

Find this line,
 modifierBank1=CB3LB
And change it (for example) into
 modifierBank1=CB3LB
If you couldn't find the line, just add it.
Next time you press 1 you will get weak clustermines and blinding lasers.
And the story for 2, 3 and 4 goes the same.

This is very convenient if you need to swap between mine-settings and missiles-settings.

You can also automize standard chatcalls. For example, Our ball is safe is "said" if you press F1.
This will reduce the risk of you getting shot while talking.
Again you need to edit you .xpilotrc or xpilot.ini
Instructions for .xpilotrc :

Find this line,
 xpilot.msg1:
and change it into
 xpilot.msg1: Our ball is safe
And again, if you couldn't find the line, just add it.
Now you need to check if F1 is linked to msg1.
Find the line,
 xpilot.keySendMsg1:  F1
If you can't find this line, then add it.
And the same goes for any number between 2 and 20.

Instructions for xpilot.ini

Find this line,
 msg2=
and change it into
 msg2=Our ball is safe
And again, if you couldn't find the line, just add it.
Now you need to check if F2 is linked to msg2.
Find the line,
 keySendMsg2=F2
If you can't find this line, then add it.
And the same goes for any number between 3 and 20.
In Windows you can't use the key F1, since windows will then try to open the Helpfile for Xpilot.

But there is more. There are special charactercombinations!

#ln will be substituted by the name of the player you currently have locked.
#t will be substituted by the number of your team.

You could now make a message like msg2=#t:#ln has our ball. If you press F2 in the game, only your own team will hear the message, "S has our ball", if you locked on to S.
For all the other charactercombinations look in this readme. Unixplayers can find it in their xpilot-doc directory.
Talkmacro's are especially useful in teamplay. (Thank you, HeadAce and H.E.R.O.)

With these talkmacro's I found an easy way to switch teams, since about 33% of all maps are Blood's Tournament.
Behold, first the Windows way and then the Unix way :

msg8=#=[#t|2|/team 4|/team 2]
xpilot.msg8=#=[#t|2|/team 4|/team 2]

And some explanation to go with it....
#= is the comparioncommand, so IF #t == 2 THEN /team 4 ELSE /team 2. This means, if you are currently in team 2, go to team 4 or else go to team 2. It allows you to swap between teams rapidly.

This trick of course only works on Blood's (or other maps with only two teams, 2 and 4).

When you are playing  Xpilot, people can see your username and hostname. (You can see this is you press 'U' during play). You can easily change this.
Windows :

Open your xpilot.ini in a texteditor.

Add this line if you want to change the user part of user@host,
 user=    username
where you subsitute username with the name you want other people to see.

Add this line if you want to change the host part of user@host,
 host=    hostname
where you subsitute hostname with the name you want other people to see.

Unix :

Open your .xpilotrc in a texteditor.

Add this line if you want to change the user part of user@host,
 xpilot.user:    username
where you subsitute username with the name you want other people to see.

Add this line if you want to change the host part of user@host,
 xpilot.host:    hostname
where you subsitute hostname with the name you want other people to see.

This doesn't really serve a purpose, but it's fun nonetheless.

Since MENU -> KEYS still doesn't work right for the Windows-version of Xpilot, I made a screenshot(rightclick -> Save as ...) of it. Of course this is the default keysetting, you can change the keys in your Xpilot.ini/.xpilotrc.