yeah, the game currently is a bit too harsh about base positioning. Otherwise your craft won't have enough fuel to fight effectively. I also use Middle East(Crete Island),Central America(Cuba),Indonesia to cover most of the countries. You won't have funding for more then 3 interceptor bases,until you start snowballing with them.
Prioritise explosives research for the missiles upgrades. Alenium,Alien Reactor,Fusion Reactor,i think?
I prefer to use more Foxtrotes then Condors(Corsairs). The only things Condor can kill on his own are light scouts and fighters. So more then one usually a waste. Corsairs can kill heavy fighters and Scouts with Plasma missiles research(Alien Reactor),so a bit better,but by then you will have too much fat targets anyway,so you need minimum 3 Foxtrotes.I keep 4 in middle east(main base,tend to have more spawns).
Foxtrotes can kill escorted targets. Practice avoiding missiles with Foxtrotes by flying under obtuse angles into firing range and using afterburners.After torpedoes are away,and all missiles missed, you use retreat and afterburners again. They will not run away unscathed,but should easily be ready for the next wave. Ofcourse,its better to kill unescorted targets first,do a quick rearm and go for escorted ones.
For the randomness of wave spawn, i suggest doing Save/Load between waves. Sometimes you can get completely screwed and get all UFO's around one base.