If you're wallowing in last place in your league, it's probably time to try something different or to simply step up your efforts for a respectable finish. If you're leading the pack, this is not a time for complacency. You must stay sharp to ward off your pursuers in the rotisserie format, or to maintain your high seeding for the head-to-head playoffs.
Make efforts to trade for notorious second-half players
There is bound to be an owner or two in your league that is frustrated with the subpar, first-half play of his or her upper echelon player. Do yourself a favor over the next couple of days and research the career second-half splits of some of these struggling players from the first half to see if an upward turn is just around the corner. If the disgruntled owner has expressed dissatisfaction with a player that you've learned has historically turned it up after the break, make a pitch for him. Chances are you won't have to give up as much for a player whose value has lessened in his owner's eyes.
Take inventory of your own team
With the above being said, take a look at your own roster to determine who needs to stay and who needs to go. You may have been suffering with a player mired in a terrible slump, while there are very capable free agents floating around in your league pool. If you've struggled in the first half, what do have to lose by shaking things up and getting rid of some dead weight? This is no time to sit on your roster with a "name" player or someone you've always liked, if you want to make a move up the standings. It's also not the time to have an infirmary of injured players taking up roster spots, especially if you're in a head-to-head league. Piling up numbers each week with healthy, active players will be crucial for your second-half success.
Be prudent with your moves and keep the lineup card filled
There are league formats that restrict the number of moves or starts that you can have during the year, but make sure you're maximizing your situation so that you don't carry unused transactions into the off-season. If you're allowed a limited amount of free agent moves, however, don't use them to speculate on players that are currently in the minors and may contribute as a call-up in September, unless you're possibly stashing some future assets away for a keeper league. Rather, keep a close eye on your league's waiver wire for players that are contributing at the Major League level now. Those are the only ones that can help your powerhouse team stay strong or your scuffling team make a move toward the top.
I've talked before about keeping your roster full of active players, in particular on the off- or travel days, when the Major League schedule is thin. This applies to both the head-to-head and roto player. With certain categories (runs, HR, RBI, stolen bases, wins, strikeouts, saves), piling up numbers is important. There's no sense in leaving a lineup slot open on a Monday or Thursday, if you have the roster flexibility to add either a hitter or starting pitcher with a favorable matchup.
Use competitors' apathy to your advantage
The All-Star break usually signifies more than a brief respite from the fantasy baseball season. It also marks the beginning of an increased focus on fantasy football. As owners of both successful and struggling teams in your league start gravitating toward the gridiron, your heightened awareness and continued efforts to improve your baseball squad will allow you to uncover hidden, second-half free agent gems that will not only serve you well for this season, but also give you some added knowledge when you start preparing for next year's draft.