What I found works well is to aggressively go after getting as many satellites in orbit as soon as possible. Getting the continent-wide bonuses goes a long way towards accelerating your rate of research, especially "we have ways" as it eliminates the wait on any autopsies. Needless to say this is most useful early on.
Indeed on my first playthrough I almost entirely skipped over laser weapons (only bothered with rifles & pistols) and went straight for the plasmas.
I'm usually following a different route.. get as many satellites up early in the game (at least 5-6) and then produce some on stock so i can react to maximum panic levels in countries before the end of the month so as not to lose the country.
Moneywise it's only very tight in the beginning and you can always do some 200$ missions to get some cash. I also don't bother saving up alien bodies for aircraft boosts or anything else as it's not very effective. Sell them off for a tidy bonus.
This might change with the new game (and for me it's a new game with all the additions) because you apparently need the alien bodies for biotech and cyber upgrades over which i'm drooling to do so hard ( want my Terminator and Agent Neo squads dammit!)
Enemy Within will be so awesome.. they simply can't fail apart from totally fucking up the base program and making the game unplayable.