All GPS tracking devices need to be able to receive at least three GPS satellite signals that are strong enough for the device to calculate its exact location.  

The stronger the satellite signals the better, so it is critical to place the device where satellite signals can easily reach the device.  Yes, satellite signals can bounce around inside the car or even off a road surface to places underneath the actual vehicle, but unless you have the time to do a some testing to see how a location will work, the following options will very likely work straight away with little placement time.

Inside the car

Satellite signals will not penetrate metal, but they will easily penetrate glass, plastics and particle timber products.  The ideal position inside a vehicle is somewhere underneath the front or rear windscreen.  Under the front dash or underneath the rear parcel tray on a sedan are ideal locations.

The driver of a vehicle might use the glove box, but if its design is such that you can't easily see the top inside of the glove box, then that might be a good location to Velcro a small GPS tracker.  Alternatively, place the unit somewhere behind the front centre consul.

Most rear parcel trays are easily accessed via the boot / trunk of the car.  The parcel tray will likely be a criss-cross of metal bracing with a fibreboard and carpet top.  If you can place the unit between that metal bracing and the parcel tray, the satellite signals will easily penetrate the fibreboard, carpet and glass above it.

Although not ideal, another possible location is under the front passenger seat of a car.  Place the unit as close to the front of the seat and the windscreen as possible.  

Outside the car

Most newer cars these days have a plastic or fibre-glass cover over the metal framework of the front and rear bumpers and this is the most preferred location .  You will need to secure the unit by first placing it in a case with a strong magnet or with tape, zip-ties, etc.   Be sure to make sure the unit's inbuilt antennae is facing upwards and that the unit is not placed underneath the metal bumper framework.

GPS trackers with an external antenna lead can be placed almost anywhere as long as the actual antenna is placed somewhere it will receive strong satellite signals. 

Check to see if a website is down for you, or if it is down for everyone.

DownForMe.org is the best place online to see if a website is down for just you, or if it is actually down for everyone.

With the huge growth of the Internet, and new websites being launched everyday, DownForMe.org helps confirm when websites are offline

Have you ever wanted to send confidential information within your work environment, to family or friends, but were afraid to do so over the internet, because some malicious hacker could be spying on you?

Privnote is a free web based service that allows you to send top secret notes over the internet. It's fast, easy, and requires no password or user registration at all.

Just write your note, and you'll get a link. Then you copy and paste that link into an email (or instant message) that you send to the person who you want to read the note. When that person clicks the link for the first time, they will see the note in their browser and the note will automatically self-destruct; which means no one (even that very same person) can read the note again. The link won't work anymore.

You can optionally choose to be notified when your note is read by leaving your email and a reference for the note.

https://privnote.com/

With Gmail, you can add a +word to the end of your email address. So, if your email is johnjones@gmail.com, you can use johnjones+xyz@gmail.com and that will also be delivered to the same email address. 

You can then also set up a filter based on the +xyz keyword to direct the incoming email wherever you want and bypass the inbox.

The +word feature is also useful for tracking emails and seeing who is selling your email address.

If you should ever be forced to withdraw money at an ATM, you can notify police by entering your PIN in reverse.  If your PIN is 1234, then enter 4321.  The ATM system recognises the reversal of the PIN and will still give you the money but, unknown to the robber, the police will be immediately dispatched to that location.

All ATMs carry this emergency sequence by law.

If your mobile phone battery is almost dead, press the following keys:  *3370#

Your phone will restart in a special way with this new reserve and the phone will show a 50% increase in battery power.  This reserve will get recharged when you next charge your phone.

The emergency number worldwide for all mobile phones is 112.  If you find yourself out of the coverage area from your mobile network and there is an emergency, dial 112 and your mobile will search all existing networks to establish the emergency number. 

The 112 number can be dialed even if the keypad is locked.

Google watches just about everything you do on the Internet with cookies that are planted in your browser.

As Google explains it:

“Many websites, such as news sites and blogs, partner with us to show ads to their visitors. To see ads that are more related to you and your interests, edit the categories below, which are based on sites you have recently visited.

Your interests are associated with an advertising cookie that’s stored in your browser. If you don’t want us to store your interests, you can opt out below.”

Want to see what Google has inferred about you, and edit the categories? Edit your Google ad preferences here.

Is a particular mobile number connected to Telstra, Optus, Vodaphone, etc. 

You can find out for free at this link.

See also:
Call direct to Voicemail / Messagebank for Optus mobiles.

In response to Tom's Comment (which is appreciated), I've conducted a check of an associate's mobile number who I know used to be on Telstra, but has changed to Optus.  The photo below is the result of the search on his number.  As you can see, it shows the "Original Network" as well as the "Current Network".