Having a vise is critical, especially for small chips, but since you are holding out of the right one, here are some suggestions:
Having the right size soldering iron and power will reduce the amount that your PCB heats up. Ideally you want a soldering iron that can quickly transfer heat to your pad so that you can get your solder on and take the heat off fast. To do this you will want to use the largest tip that you can find that still gives you the precision needed for what you are soldering. Adjustable temperature soldering irons are nice, but you need to also make sure that your iron is able to output enough power to keep your iron at the temperature you want it at.
If you have a large ground plane, you will most likely have to heat it up in order to get good soldering. You can added extra space at the edge of your PCB with no copper for you to be able to hold on to. If you aren't holding it where there is metal then you are more then likely over heating your board and should look at my prior suggestion.
But, with that said, you should really consider getting yourself a nice vise that lets you put your board at any angle that you want, this will really help with getting a great soldering job. The next investment you should consider getting is either a better soldering iron and/or nice lighting.