Literally, Teshuva means coming back and being close to Hashem: אֲנִי לְדוֹדִי וְדוֹדִי לִי. The whole idea of Elul is being alone with Hashem and being His beloved friend. My Rabbeim have told me that being close to Hashem is everything, and if you have that, you have it all. I recommend davening specifically for this. And I have no: סָפֵק doubt that Hashem has Gevaldige nachas from such a Tefila!
כְּבְיָכוֹל (If it were possible to talk about Hashem like a human) how do you feel when a person tells you that he wants to be close to you? You love that person more than anyone else, and you'll do much more for him than for other people. This is a great way to be Zoche B'din on Yamim Nora'im and winning Hashem's favor. Also, R' Yisroel Salanter Zatzal said that a person should make sure that he becomes a: רַבִּים צְרִיכִין לוֹ someone that the public needs. Since you're needed by the Klal, your chances of Chaim and a good life in general are much greater. There's nothing like Zikkui HaRabbim!
R' Chatzkel Levenstein Zatzal mentions a Rashi in Brachos that when you praise Hashem you are close to Him. The Meshech Chochma says that: וּבוֹ תִדְבָּק עקב י כ “you shall cling to Him” means having Bitachon. We see that praising Hashem makes you close, whereas having Bitachon makes you totally close and Mamash sticking to Hashem. This is similar to the Sefer Ha'Ikarim who says that the biggest: שְׁבַח praise you can give Hashem is having Bitachon in Him.
Trusting a person is the best form of praising him. In Sefer Shaarei Teshuva, Rabeinu Yonah says that a person who praises Tzadikim has a great Zechus until Shamayim. And in Mishlei, Rabeinu Yonah says that having Bitachon gives you Schar: מֵעַל שָׁמַיִם higher than Shamayim, which seems like Hashem Himself. (Chazal say that a person who has Bitachon in Hashem is Zoche to become like Hashem Himself).
Notice how basic positivism is what makes a person close to Hashem. Either thank and praise all day, or calm down and have Bitachon; either M'halech makes you happy and positive. And Dovid said: וַאֲנִי קִרְבַת אֱלֹקִים לִי טוב תהלים עג כח all I'm interested in is just to get close to Hashem. If you learn Tanach, you'll see how Dovid was indeed the most positive person, full of singing and praising, and the #1 Baal Bitachon. The Passuk: וּבוֹ תִדְבָּק עקב י 5 "you shall cling to Him” which means Bitachon according to the Meshech Chochma, fits in perfectly with the Chazal that a Baal Bitachon is like Hashem Mamash, since you are indeed: בוּק attached to Him.
However, when it comes to Teshuva, you may actually be super close but you don't realize it. That's why the Rambam in Hilchos Teshuva says that a Baal Teshuva shouldn't think that he is: מְרוּחָק וּמְשׁוּקָץ distant and repulsive. He is actually M'kurav (close) and a much-loved Yedid (friend). This is very important, and it harms all those who are always struggling up-and-down. They are true Baalei Teshuva, since שֶׁבַע יִפּוֹל צַדִּיק וָקָם משלי כד טז A Tzaddik falls seven times, and gets up; this is the normal process. They are in pain over their sins, and they don't really believe nor feel that they are close.
They fall prey to the dangerous and much prevalent Yetzer Hara of putting yourself down. You need a special Avoda to keep Chazzering this Rambam and believing how great and close you really are. I know a Yungerman who Davka when he fell and was Nichshal, a big Mekubal told him that he sees the Shechina on his face. This can be because a person who is always working on himself is always a Tzadik, like it says שֶׁבַע יִפּוֹל צַדִּיק וָקָם משלי כד טז A Tzaddik falls seven times, and gets up, and the pain he has over his sin makes him even greater, since: לְפוּם צַעֲרָא אַגְרָא אבות ה כב the reward increases according to your pain.
When you're always aiming in a certain direction, it's as if you're always there, even when you aren't really there.