How do we know if we've had a "successful" Lent then? Perhaps you completely blew your Lenten sacrifice...two days into Lent. You were determined to give up chocolate and then found yourself eating just one brownie, one piece of candy....Maybe you were determined to put aside time every day for extra prayer, and you sort of lost your way half-way through the 40 day journey, wandered off and never got back on track. Is your Lent a loss?
On the other hand, may be you kept up all your Lenten aspirations. You stayed away from beer, caffeine and quarreling. You made it to every single Stations of the Cross at your parish, and filled the out a terrific check for the charity of your choice. Is that a successful Lent?
I suspect Lent is more about walking with Christ in the desert than checking off boxes marked "Prayer, Sacrifice, Alms" (although those are mighty important means of walking with Christ). After these forty days, what have you learned about your Faith? What have you learned about Christ? Is your relationship with Him stronger, clearer? Has love for Christ been strengthened in you? Are you more like Christ today than you were a few weeks ago?
I have to say, I've been down on myself for not having a very "successful" Lent. My chosen sacrifice flew out the window. The sacrifices God chose for me were burdensome indeed. I spent quite a bit of Lent physically suffering. I found a form of meditation I hadn't used before to be very helpful, but I didn't plan it. I'm very sad about some family issues, and those won't go away after Lent is over.
Has it been a successful Lent? I pray so. I know I'll be trying to sing my "Alleluias" and "Gloria" with heartfelt love for He Who Has Risen. My Lent may not have been successful in the way I wanted it to be, so I must rely on Christ's Success. It's the only success that counts anyway.