On a serious note, make sure all your uniform items are marked with your name according to whatever your Drill Instructors taught you, make sure you have two pairs of socks for every day of wear so you don't get blisters on your feet from all the humping you'll do, and keep a positive attitude. You're going to 4th phase of Boot Camp, but it's not that bad
We didn't have MCT when I went through boot-we had RFTD for one week in Boot, then on to Infantry Training School (ITS) after graduation for those of us in the 03 field-which is now SOI at San Onofre (13 area) at CamPen where you're reporting to. Just thank your God that you're not going to MCT-East with all the heat and humidity in the summer, and raw, wet cold in the winter. At least the climate is warmer and dryer in CA. You're not going there to have fun. You're not going there to make friends. Just get in there, do the training, and get out without making a name for yourself. STFU, keep a low profile, and do what's expected of you.
And whatever you do, don't stand in line in front of the shitters on some range out there at Pendleton, waiting for some BAM to give you a BJ for half of your meager paycheck. Yes, it's happened.