I'm a big fan of miniature modelling and painting, one of my favourite tools for finishing off large groups of models is Quickshade. Designed and sold by Army Painter the large can version of Quickshade is a strong glossy varnish coupled with a wash. Being a shade of your choice (Soft, Strong or Dark) it can really smarten up those dodgy brush strokes for those of you without the eyes to get right into the detail anymore. I have been painting for more than 25 years now and I have now a distinct lack of desire to get right into the fine detail these days! Coupled with the shade is the varnish which provides a tough and durable polyurethane coating that will last. Polyurethane is a highly resistant material and is used in many high resilience goods such as high performance sealants and adhesives, so you know you are getting quality.
Whilst it can take a while to dry this gives you enough time to make sure that you have the varnish and more importantly the shade in the right places. You can still work with it up to about an hour after application and move thicker areas of shade around with a paintbrush to reduce the bunching effect and too strong a tone in the recesses of the model building up. The only downside I would say is that it dries glossy which means if you want tabletop ready miniatures you really have to give them a second coat of matte varnish, either spray or painted matte varnish will do and will only give the model more protection from knocks and bangs during tabletop warfare!