[Q] How do I choose which independent variables to put into a multiple regression?

Hi, doing my psychology dissertation and it’s due so soon and I’m so stuck!!

Looking at predictors of theory of mind performance. IV/Predictor variables were: executive function , 5 personality traits, autistic traits and empathy. Was going to put in the IVs that are significantly correlated with my DV

4 IVs correlated with my DV but some of these are significantly correlated with eachother and some of my other IVs that did NOT correlate with my DV.

e.g. TOM significantly correlated with agreeableness, but agreeableness also significantly correlated with: empathy, EF, extraversion, autistic traits and neuroticism

Do I put all the IVs correlated with eachother into a regression so I am controlling for them? Problem is that would give me 8 predictors not including age or gender?