Get a medium sized lockbox, like something used for cds where the cd inserts come out of them. I use something similar to keep my pipes and weed in.
Use smaller sized ritual tools- things easily hidden in said lockbox. The size doesn't much matter as long as it suits your needs.
If possible, find a park that you feel comfortable being in at night. Graveyards work fairly well since not many people tend to hang around there at night.
I'm assuming at this point you are under aged. So getting out at night might be an issue. If you have a decent sized enough bathroom, you could try there, but you said you live in an apartment so that might also be an issue.
You could try working on smaller rituals. Like having a small plaque or tapestry with your chosen design that you can concentrate on in front of a candle. Then work out a mantra sigil and use some buddhist prayer beads to go over it. Might be interesting for you to de-sanctify the beads.
Use your imagination!
<using Pup's lock box idea> To hide in plain sight is one of my favoured ideas. A false power point wall plug that houses a storage box is an old trick but still works well and it is easy for most to make their own version. The average wall space allows for a 4inch by 4inch by 2inch high box. If in a rental place leave the power point face plate covering the hole when you move but take said lock box ;-)
Hopefully these guys gave you some good ideas and eventually you can move on to more of the mental. Good luck.