[1] : WordNet (r) 2.0

step up
     v 1: increase in extent or intensity; "the allies escalated the
          bombing" syn: escalate, intensify ant: de-escalate
     2: speed up; "let's rev up production" syn: rev up
     3: make oneself visible; take action; "young people should step
        to the fore and help their peers" syn: come to the fore,
         step forward, come forward, step to the fore, come
        out
see also:
escalate intensify de-escalate rev up come to the fore step forward 
come forward step to the fore come out 

[2] : Moby Thesaurus II by Grady Ward, 1.0

119 moby thesaurus words for "step up":
   accelerando, accelerate, acceleration, accost, advance, aggravate,
   aggravation, amplify, approach, appropinquate, approximate,
   bear down on, bear down upon, bear up, beef up, beefing-up,
   blow up, blowing up, blowup, charge, close, close in, close with,
   come, come closer, come forward, come near, come on, come up,
   complicate, concentrate, concentration, condensation, condense,
   confront, consolidate, consolidation, crack on, deepen, deepening,
   double, draw near, draw nigh, drive, electrify, encounter,
   energize, enhance, enhancement, exacerbate, exacerbation,
   exaggerate, exaggeration, explosion, gain ground, gain upon,
   galvanize, generate, getaway, hasten, heat up, heating-up,
   heighten, heightening, hop up, hot up, hurry, hurry up, impetus,
   information explosion, intensification, intensify, jazz up, key up,
   loop in, magnification, magnify, make complex, narrow the gap,
   near, open the throttle, pick up speed, pickup, plug in,
   population explosion, proximate, put on, put on steam, quicken,
   quickening, race, ramify, redouble, redoubling, reinforce,
   reinforcement, rev, shake up, sharpen, shock, short, short-circuit,
   sidle up to, soup up, speed up, speedup, step down, step on it,
   stiffen, strengthen, strengthening, switch off, switch on, thrust,
   tightening, triple, turn off, turn on, whet

Ball Up >> B Words
Ball Up, definition of term: Ball Up
ball+up_pag1.html

Bang Up >> B Words
Bang Up, definition of term: Bang Up
bang+up_pag1.html

Backed Up >> B Words
Backed Up, definition of term: Backed Up
backed+up_pag1.html

Back Up >> B Words
Back Up, definition of term: Back Up
back+up_pag1.html

Ante Up >> A Words
Ante Up, definition of term: Ante Up
ante+up_pag1.html

Act Up >> A Words
Act Up, definition of term: Act Up
act+up_pag1.html