You can often make an educated guess at the main word if you remember the following (and if you have a basic understanding of Latin - that very under-rated subject!

). Looking at the score and hearing it in your head also helps sometimes in making a reasonable guess.
-issimo means
very something
poco... means a little something
-ando is the Italian equivalent of -ing - so it's "doing something progressive" instruction rather than being a basic indication of tempo - i.e calando, accellerando, etc.
-etto means less so than the word would mean without the -etto at the end.
con means with (so the next word is a noun)
-ato is a past participle (the English word would end in -ed)
I'm sure there are more generalisations - that's what occurs to me now. What really stumps me is the German words! How can you remember something that you can't even pronounce!