One guard pass to rule them all

Even world class athletes actually use less than five guard pass techniques- one or two are their "favourites", and then the others are for dealing with something that truly requires a specialized technique.

• Pick a "favourite" guard pass
• Practice how to enter the staging points from which your favourite pass is naturally available. You are going to need to know more than one, since your opponent can play all kinds of guards against you. 
• Study how your guard pass can be countered. Granted, just about all of the counters require you to "mess up" in some capacity. It is important to be able to recognize when you are "messing up", and how to control the damage when you are messing up (hint: re-establish your staging point)

Note that for dealing with something like deep half or lockdown, you need specifically adapted techniques because the body positions are so peculiar with those.

Yes, spamming the same guard pass again and again and again is a legit strategy. Building on from the third point, if you hit your guard pass just right, your opponent literally cannot stop it. Seriously, watch Lucas Lepri vs. Roberto Satoshi de Souza. You would think that R. S. de Souza's RDLR game ought to send Lucas Lepri packing because RDLR is a natural counter to the knee slice, but noooooo! Lucas Lepri sends Souza packing because his knee slice was just so on point.