Get a razer blade and cut the side of the cup vary carefully making sure not to cut anything but the cup and then cut the bottom. I always start my babies in those Red plastic cups and transfer them, and this works every time.
thankyou!...and also, when Should i transplant? like right now i just have the 4 leaves i think..so like how long till i should do it?
I usually wait about a week and a half max after sprouting from the soil. You could probably wait a little bit longer, but you dont want your roots to outgrow the cup so you have to be careful. Better sooner then later. It wont hurt your plants by doing it earlier. So basically whenever you feel its ready, but dont wait to long.
Thats how i start mine too. I always just make sure the soil is good and moist so it stays together and turn the cup upside down with the stem between my middle and ring finger and tap the bottom of the cup. everything comes out in one easy to handle chunk. Always worked for me.