Strat cards

It's going to take luck unfortunately.

I haven't bought any strat cards myself, just use the free daily stat from objectives to always trade up, i.e. common --> uncommon --> rare, but if you have crap luck form the dailies, this can take max 40 days per rare since you need 8 common per uncommon and 5 uncommon per rare, and then, you don't know which rare you will get, it is random.  Once you have two rares, you can trade those in for a specific offensive or defensive strat and you'll get a selection out of 10 but again, it is random so you might not even get speed strats.

The only other way is to buy strat cards from the market and hope you have decent luck to not just pull common cards because if you do, it will cost $200K per rare and you're relying on luck to get a speed strat.  You just have to follow the same trade up strat as above but it can get expensive if you're luck isn't right.