Here are a few tips and tricks for building a mock draft:
1) A Sixth Rounder is Not Going To Start: Nor will a fifth rounder, or a seventh rounder, or even a fourth rounder. Of the last 5 or so drafts I've seen, every one has the Jets drafting a pick with a line like "Can replace X player" or "Is an absolute steal." Guess what, if they're that good, they'd have gone sooner. As a general rule of thumb, expect teams to go BPAAPON(Best Player at a position of need). They will probably have expectations of starting of these players, with the late third being a gray area. When mocking late round picks, know that teams will draft for best player and that they will not fill any need of the team, even if is a position of need. THIS INCLUDES RUNNING BACKS. If the Jets let Keller go and don't replace with a FA, they will probably be drafting a tight end in the first three rounds.
2) Don't Mock Who You Want, Mock What You Think: The biggest problem with mock drafts as a fan is that you have the players you want the team to get. So when you are drafting, you subconsciously try to alter your mock to get as many as these players as you can. Its hard not to. You probably go on a draft site, and you see the probable range, and its "Rounds 2 to 4." A good mock draft puts that at the late 2nd to early third in terms of likelihood. But a fan might want this player for his team, so he'll slot him to them.
3)If You Think He's A Steal, He's Not Going to Be A Steal: If you see a guy that pundits say will be a sleeper, he probably will be drafted 10-20 slots higher than projected. Demario Davis is a great example. Brian Quick of the Rams is as well.
4) Know What is Wanted, and Expect Trades: It is important to understand the needs of teams and the talent available. Expecially with the new CBA, picks will be flying around. Expect bidding wars for players that are falling and are contested. For example, Dee Milliner is far and away the best corner in the draft. There are a lot of teams in the 10-15 range that will want corners. A team in the 5-10 range (like the Jets) can capitalize of the opportunity to trade down. In contrast, the top half of the draft is filled with pass rushers, so there won't be too much fighting over players. So, even if you aren't predicting trades in your mock, the goal is to be as close to the real order as possible, so anticipate trades.
5) Understand the Risers and Fallers: The combine is the number one way for a prospect to shoot up draft boards and be in hot contention. Remember workout warriors like Dontari Poe will be picked high, no matter what. Understand that character issues, on the other hand, can drop a prospect at least 10 picks and, at worst severity, out of it all. Expect minor issues to be small drops, and major ones 20-30 picks (like Mike Adams).
6) It will all be mostly wrong anyway: In 2010 it was Tyson Alualu. Last year, it was Bruce Irvin. There will always be that major "Wha!!" pick that no one saw. Your draft won't be perfect. Just try your best and have fun.