Dover took the lead on 15 minutes when Miller turned well and slotted the ball into the bottom corner.
Moments later Guiseley almost equalised but Kevan Hurst's corner was headed wide by Jake Cassidy.
Hurst then had a couple of attempts of his own, including a 40-yard effort, while Miller lashed an effort just wide as the visitors looked to double their advantage.
Miller also hit the post after the break but the Whites did make it 2-0 on 67 minutes as Ricky Modeste headed home from close range.
Miller grabbed his second with a penalty on 81 minutes and Ross Lafayette added a spot-kick of his own in added time to seal a comprehensive victory.
Match report supplied by the Press Association.
Match ends, Guiseley 0, Dover Athletic 4.
Second Half ends, Guiseley 0, Dover Athletic 4.
Goal!  Guiseley 0, Dover Athletic 4. Ross Lafayette (Dover Athletic) converts the penalty with a.
Substitution, Dover Athletic. Mitchell Pinnock replaces James Hurst.
Substitution, Dover Athletic. Chris Kinnear replaces Ricky Miller.
Goal!  Guiseley 0, Dover Athletic 3. Ricky Miller (Dover Athletic) converts the penalty with a.
Substitution, Dover Athletic. Ross Lafayette replaces Moses Emmanuel.
Substitution, Guiseley. Derek Asamoah replaces Kevan Hurst.
Substitution, Guiseley. Michael Rankine replaces Ashley Palmer.
Goal!  Guiseley 0, Dover Athletic 2. Ricky Modeste (Dover Athletic).
Substitution, Guiseley. Alex Purver replaces Simon Walton.
Simon Walton (Guiseley) is shown the yellow card.
Second Half begins Guiseley 0, Dover Athletic 1.
First Half ends, Guiseley 0, Dover Athletic 1.
Goal!  Guiseley 0, Dover Athletic 1. Ricky Miller (Dover Athletic).
First Half begins.
Lineups are announced and players are warming up.
Ricky Miller scored twice as Dover boosted their National League play-off hopes with victory at in-form Guiseley.