Tissue covering? Wow that's a flashback to the 60's.

Start by sealing the structure with a few coats of dope, thinned 50% dope 50% thinner. Sand lightly with 400 grit. Dampen the tissue with a fine mist spray bottle and flatten it on a smooth table, no it'll never lay completley smooth. Use the capalary attraction of the water to stick the tissue on the structure. Cover each section with a separate piece of tissue, I.E. bottom wing left one piece, top wing left 2nd piece, etc.

Carefully smooth out the wrinkles, patience is important here as tissue wrinkles easily. Dope the tissue edges to glue it down. Overlap slightly as you lay down the next piece of tissue. If it drys and it's not perfect, paint more dope or straight thinner and carefully lift as the fresh dope loosens the dry dope.

Once it's completley covered, thin some dope 80% thinner and 20% dope. Using a soft wide brush dope the tissue lightly holding it UPSIDE DOWN! Any dope that bleeds through the tissue will now be on the outside and you can wipe off runs with the brush dampened in thinner. Only do one side at a time and allow it to dry. The next coat apply thinned 50/50. Once it's sealed you no longer have to hold it upside down. Apply enough coats that the surface is sealed. If this is a glow powered plane, apply at least 10 coats thinned. Other power just seal the tissue and decorate using colored dope.

Enjoy, a good tissue job is a work of art.