If you use the ion bomb, place it over a barrier, intersection, or a winding path. Some winding paths are located in meander (the 3rd endless map), gully (2nd campaign endless map), outpost (the 1st endless map), shunt (the 6th endless map), etc.
The egg nests are found only in campaign 2. Save up enough energy to use the orbital laser. Once that is done, wait for a boss to come up. Use the orbital laser immediately when the egg is about to hatch. During a boss wave, when you use the orbital laser, the first thing you should target is the egg. Set the laser crosshairs on the egg nest before the laser fires. The egg will die in a half a second if done correctly. Then kill the boss aliens. If you use the orbital laser before a boss arrives, you'll most likely regret it.
As we all know, snipers are long range and do loads of damage. And the beam towers are just as powerful, but have less range. Take advantage of their range differences. If your commander is at least lv. 10 or above (reccomended artemis armor) set your sniper and beam tower in his morale. The beam tower must be placed near a barrier to guard it. Snipers cannot be set as near to the barrier as the beam towers are. Just a little bit farther, but stay in the commanders morale. Make sure that they are fully upgraded and their range covers a barrier. Very useful.
When you use the orbital laser (if you have it) and you end the wave using the orbital laser, if the laser is still shooting, set the laser crosshairs to the beggining of the map, where the aliens spawn and you'll get more kills, resulting in faster cash and the wave ends sooner. (use the orbital laser on bosses like the warriors, queens, or anthropods. Usually arachnids are after them.)