These four verses eloquently put the main things that block us from our goal in perspective, and how to overcome them. Here are the verses.
Heb 12:1 Therefore, since we also have such a great cloud of witnesses surrounding us, putting aside every weight and [the sin that so easily ensnares us], let us run with patient endurance the race that has been set before us,
Heb 12:2 fixing our eyes on Jesus, the originator and perfecter of faith, who for the joy that was set before him endured the cross, disregarding the shame, and has sat down at the right hand of the throne of God.
Heb 12:12 Therefore strengthen your slackened hands and your weakened knees,
Heb 12:13 and make straight paths for your feet, so that what is lame will not be dislocated, but rather be healed.
Unpacking, we see the first instruction is to "put aside every weight". Weight in this sense means burden... and significantly, "every" means EVERY". We struggle here because there are MAJOR things that we think we MUST take care of, because "waiting on the Lord" might not play out well at, say, the mortgage office; and minor things that we say, why bother God with that? But when we become Christians, the only burden to carry is Jesus' burden. Boiled down, worry keeps us from the goal- and we must set it aside, and FOCUS on the goal ahead.
Our second instruction is to also put aside "the sin that so easily ensnares us." KJV translates "ensnares" as "besets", and here it is a combination of three Greek words which indicate a runner being surrounded in his competition by competitors trying to stop him ON ALL SIDES. We have distractions from the goal in every direction- some of them from the inside (the weights or burdens) and some from outside (the distractions that lead us off-track in all directions).
For a Christian, we have not only the clear goal of salvation, but several examples of how do do it- especially Jesus, who counted even death on a Cross one more thing to run through as he focused on the prize that lay at the end.
The third enemy on our way to the goal is enlightened in v. 12:12- letting our morale flag along the way. In between these sets of verses, the writer reminds us that MOST of us haven't yet gone to the point of shedding blood as Jesus did- we have effort yet to give. He also mentions that at times we are "chastened" by God, as a child is chastened by a father. Sometimes the effort discourages us, sometimes it is the trials along the way. What the writer wants us to remember is two-fold: one, that we can handle more than we think, if we try; and two, that the mere fact of troubles means we have GOTTEN SOMEWHERE. If from Satan, then we must be going the right direction; if from God, that we have achieved the status of His Child.
The final stumbling block is the one we put before ourselves. Along the way, we stumble. But that stumbling only becomes injurious if we are OFF-Track. If we take the straight, smooth trail that Jesus points us out- a path free of the distractions, the sin, the self-defeatism- we may yet stumble, but we won't "break an ankle" doing so. We will be able to get back up and keep going, getting stronger as we go.
The main thing is a focus on the goal. And like I said at the start, even a non-believer can profit from that. But if you are a Christian, the goal is that much better- and worth the trials to focus on and run toward.