The web is full of observing and imaging tips.  You should spend quality time reading the opinions of the many dedicated amateurs on the web.  Here are a few things that don't get talked about much:

• When using the Meade f/3.3 focal reducer, keep the spacers to a minimum.  If not the edge illumination will be poor and coma will be severe.  I now use the following combination in series:  Telescope with standard male SCT thread, f/3.3 reducer, Orion SkyGlow SCT filter, NO SPACERS, M42x0.75 by M42x1.0 adapter, MX7C camera.  This produces f/4.3 according to my astrometrics.  My recent images show improvement with this combo.
• The SkyGlow filters the light less severely when it strikes at an angle, so hitting it with f/4.3 rather than f/10 helps compensate for the focal reducer's light-loss at the periphery. 
• When viewing planets or double stars, lose your night vision.  You want to optimize your human optics.  If you can see very faint objects you cannot see bright objects as sharply.
• LPR (light pollution reduction) filters work on objects other than nebulae when imaging in bright lights (as I normally do).  I routinely use them for star clusters.  Occasionally I succeed at galaxies too.
• If you view or image in a light-polluted area, larger optics are still worth the money.  Don't think you need less aperture because of skyglow.  Choose narrow-field targets near the zenith and apply lots of magnification to spread the glow out.  Larger scopes will tolerate high magnification well, especially if you use LPR filters.
• Never apply a red pencil to your observing lists or field notes.  Under a red light it disappears.

Mars 2003 Telescope Comparisons:

Note:  Since writing this comparison I've researched central obstructions in telescopes and the merits of refractors vs. reflectors.  One of the best explanations can be found at Thierry Legault's site.  It is no surprise that the 5" Mak produces aesthetically pleasing views of the moon, while the 5" achromat yields sharper detail of low-contrast objects.  The central obstruction on the Mak is even bigger than the secondary itself; you can see an internal cone inside.  This is typical for Maks; some even come with external obstructions that can be removed.  Without such extra obstruction the secondary cannot block incoming light from reaching the eyepiece directly between the edge of the secondary and the inside of the internal eyepiece baffle.  So high-contrast objects like craters have excellent contrast, while low-contrast rilles are there but harder to find in the Mak than in the much cheaper achromat.  Of course the Mak is free of false color and produces high magnification with ease.

1.  Meade 10" LX200 f/10 SCT:  Top honors of the four, as expected.  With the mild temperatures cooldown has not been an issue.  Even "quick" looks have been acceptably steady, contrast seems very good with Mars surface coloration easily discernible and polar cap clear as day (even as it recedes for the summer).  Unfortunately I've had few opportunities to take astrophotos (see "Planets").  This scope handles magnification very well and is a joy to use if you have time to set it up.

2.  Meade 5" LXD55 AR-5 Achromat:  Very good, somewhat surprising.  Normally  false color issues hinder this scope on planets but Mars has a pretty narrow range of color.  Contrast was close to the 10" SCT and very pleasing.  This scope is a little dimmer than the 5" Mak (another surprise) but views tend to be steadier and resolution seems just slightly better.  This scope looks like a telescope is supposed to; I might be guilty of favoring it.  Just don't aim it near the zenith.  Even if you clear the tripod legs you'll be laying on your belly to reach the eyepiece.

3.  Meade 5" ETX-125EC Mak:  Very good optically as expected.  It was a tough call to put the AR-5 ahead of it.  This scope achieves high magnification more easily than the AR-5, and produces more pleasing views, but the resolution isn't quite as good if you really scrutinize it.  This might be a cooldown issue; the Mak unfairly gets the grab-and-go treatment.  It's also a little shaky and deserves a better mount.  The optional electric focuser helps a lot, but Meade should come up with an LXD55 Mak version since many folks polar mount their ETX just to overcome motor vibration.  Meade's 7" Mak is void of these shortcomings if you can afford it, and would tolerate unsteady air better than the 10" SCT.

4.  Orion 3.1" ShortTube 80 Achromat:  Satisfying views but a little short on magnification.  Polar cap was easily discernible at about 125x (as high as I could go), used this scope to monitor the shrinking size.  This scope made Mars look the reddest due to its small aperture, and this pleased the casual viewers the most.  You can have this scope up and running in 60 seconds so it gets the most use.