Best practises to avoid blowing up water lines and connections is to open up your sink water tap when you first turn on the city water connection. On the hot water tank there is normally a pressure relief valve (mine is on the outside access hatch area). If the tank has lots of air in it that will stop the tank from filling up all the way. When you connect to city water and open the by pass valve (assuming you have one) to allow the hot water tank to fill - you should also go outside and open the pressure valve on the hot water tank and wait unit the water starts to run out of the valve - that way you know the tank is full of water and not just air before you
light it up.
Edit to add: Another hint is if you have been using the hot water tank and want to drain it, its best to open the pressure relief valve before you try and take the hot water drain cap off. Otherwise the cap is likely to shoot off and never been seen again. Have learned that lesson the hard way more than once