"[N]either have angels ceased to minister unto the children of men. For behold, they are subject unto him, to minister according to the word of his command, showing themselves unto them of strong faith and a firm mind in every form of godliness. And the office of their ministry is to call men unto repentance, and to fulfil and to do the work of the covenants of the Father, which he hath made unto the children of men, to prepare the way among the children of men, by declaring the word of Christ unto the chosen vessels of the Lord, that they may bear testimony of him." (Moroni 7: 29-31.)
Note that angels show themselves to those "of strong faith and a firm mind." Also, that the visit will require them to whom such visits come to "bear testimony of [Christ]" as a result of those visitations.
From Joseph Smith:
"A fanciful and flowery and heated imagination beware of; because the things of God are of deep import; and time, and experience, and careful and ponderous and solemn thoughts can only find them out. Thy mind, O man! if thou wilt lead a soul unto salvation, must stretch as high as the utmost heavens, and search into and contemplate the darkest abyss, and the broad expanse of eternity—thou must commune with God." (TPJS p. 137.)
Note that the "imagination" is not useful in gaining communion with God. Fanciful, flowery and heated imaginative thoughts will detract, not contribute, to knowing Him. The only way is to possess the same mental state as Moroni refers to - careful, sober, solemn, deep thoughts are required. The mind must reach into heaven as well as the darkest abyss. The opposition of things in this creation and the balance of those opposites will cause you to encounter the worst as you strive to enjoy the best. All is kept in balance throughout the process.
A person can't imagine they have salvation. They must "know" they possess it. The heavens should declare it to them. When the heavens bestow this knowledge upon a person, it is an anchor to their soul and they will never fall. But until then, a person needn't suppose they possess something which God has not declared by His own voice to be theirs.
True teachers will labor to help you understand how real, deliberate, attainable, and necessary this process is to engage in. They will not ask you to follow them. They will teach you how to follow God, and obtain from God knowledge of salvation. False teachers will distract you. They will tell you all is right, that there is enough good being done in your life to merit God's favor, and that it is not necessary for you to do more than belong to a privileged group.
You cannot possess the knowledge which will save you until you have learned for yourself that God lives, and that He has promised to you eternal life.