Have your math down cold. Both IV and retail. Know how to pick apart a reading problem and toss the garbage. Find what the problem wants-number of tablets or mls of liquid- and find the things that apply to that answer. Know the metric system-kg, gm, mg, mcg, and how to move between them- 1 gm=1000 mg, 1 mg=1000 mcg, pounds to kg-divide pounds by 2.2, etc. I've been a hospital pharm tech for a very long time and lead IV tech, IV instructor and pharmacy math instructor for about 20 years. Know what info that by law has to be on a retail label. Know the schedule drugs and the general laws around them. Good luck.
PS-If you have the option, get into a hospital pharmacy and push yourself and put your knowledge to good use.