It has to be said that I learnt the best way to cum; I get a vaginal orgasm, a clitoral orgasm and gushing all at the same time or sometimes individually
Here is the trick. Think of the sex toys that have that hook sort of shape I think they are called a G spot stimulator. You can use one of these or get your partner to their fingers forward and apply pressure to your front wall in long strokes. If you are using your partners fingers, get them to curl them forwards (but be careful of long finger nails!).
Once you start to build with this pressure then you want your partner (or you) to switch to stimulating your clit. Start with circular motion, not too much pressure and wait until you are already quite wet (or use lube that speeds things up

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Then you want to switch back to your G spot, then clit, then if you can both (that is why so many women like the rabbit)
Now for the BEST bit. If you want to squirt then I've found a really good way to do this is tapping! You get yourself really turned on, really wet, then when you clit is hard and worked up cup your fingers in gently start to your clit. You will need to figure out what speed and firmness suits you, but if you mix the clit tapping up with circular motion with your fingers you might just find yourself gushing uncontrollably
The key is keep stimulating your G and clit either alternately or together.. and don't forget to tap, tap, tap.