All of the above is great advice...simandl, using the bow and developing left hand. I would add triads! Play major, minor, diminshed and augmented triads just over the first five "frets" (from low E to C on the G string -fifth "fret"). It's a practice regime I got from Gary Willis and it is pretty mind blowing. If you want to know more about it, feel free to send me a message. Or just check it out.
Good idea from above to introduce the double bass gradually and if you're using an EUB, you won't be short of volume and feedback won't be an issue.
the Latin bass book by oscar stagnaro is the best Latin book I've ever seen. I use it inside and out - sometimes I just put a metronome on or a drum groove and play any Latin tune as swing, it's great for reading!
Anyway, good luck.
mike