You can trade with other players by going up to them (3 meters I think, correct me if I'm wrong) and right clicking their character. Then click "trade" and you can give them energy credits and unbound items.
I'm really sorry that I haven't been keeping this thread active right now, I'm really busy with RL and the likes, anyway, I'd appreciate it if anyone can post a couple more tips while I'm inactive, here's another tip.
Skill Points let you level up in the game. You can also train your skills with SP. You also gain Expertise in the game. Your officers use Expertise to train their skills.
If you run low on Expertise (either by doing Rep/Fleet projects etc) you can always stock pile more by doing the special featured series runs (Breen, Devidans, Jem Hadar etc) or doing the Mirror Universe events that are on during the day.
Although not necessary skill bonus items can be bought from exchange to get extra EXP too but they can be expensive. Remember use Q while you can to get a free 4 hour bonus until the end of November I think?! That or until the start of Season 8!
On duty duty officers can improve your ship stats. For example, some tactical officers can shorten the cool down on abilities like tac team, some science officers can shorten transwarp cool for down, and so on.