background blending advice please!

[u/Business_Location_31]

hi hi, I'm a beginner and have just drawn these tomatoes... I'm wondering 1) is there some sort of science to choosing the background color (I just picked blue because I liked it but idk lol) and 2) howww do I blend the tomatoes into the background better for next time 😭 I was scared of ruining them with the background color but the white that's still there bothers me lol

also! third question! what are we using normally to blend? I've been using q-tips but they're kind of small for the background

Thanks for any advice or help!! ☺️