For crystallization, you have to concentrate your peptide up to 10 mg/ml if possible otherwise lower conc. up to 3 to 4mg/ml also can be used. there are specific type of plates which has been designed for crystallization. you can use any type of crystallization plate. add 2 microlitre your conc. peptide along with crystallization buffers which are commercially available from Hemilton company. this is just an superficial idea about crystallization. for more minor things, refer some old paper.   

Thanks for your suggestion. Will look into some more paper also.

And my other doubt is that does hydrophobic transmembrane domain peptide is crystallizable? Does it will have any interferences?

For crystallisation, membrane proteins are usually solubilised in aqueous solution with detergent rather than in organic solvents (though organics are used for NMR).  The key is finding a detergent that the protein is happy in (though with a single TM helix this shouldn't be too tricky). Common detergents are b-octyl glucoside, LDAO, DDM. I'm not sure if any monotopics have been crystallised from organics.

If your protein is only 28 residues of helix, what questions do you anticipate the structure  answering? If CD, your poorly dispersed NMR spectrum, and maybe some sec struct prediction, tell you its a helix, what do you learn from the structure if it turns out to be just a helix? It's worth giving this some thought before embarking on the long and rough road to crystallise a membrane protein.

be careful - small helical membrane proteins are structurally influenced by their environment and since the properties of detergent environments are very different from lipid environments this could lead to misleading results. It is possible to get preliminary results from proteoliposomes with CD and with IR - the best way to characterize small helical membrane proteins is to use solid state NMR - see Zhou & Cross Ann Rev Biophys 2013 and Murray et al Accts Chem Res.

Getting crystals of membrane proteins and peptides is always tricky. These objects prefer to reside in a membrane, not in a crystal. But there is a lot of literature on this which you can consult. If you use search terms like 'lipid cubic phases' or 'lipid mesophases'  that will get you on the right track.

If you want just to orient your peptides in a parallel fashion as in a membrane (so: better than a crystal) you can squeeze them between microscope slides, and they will do that for you. Check out: Bak M, Bywater RP, Hohwy M, Thomsen JK, Adelhorst K, Jakobsen HJ, Sørensen OW, Nielsen NC. Biophys J. 2001 Sep;81(3):1684-98. Conformation of alamethicin in oriented phospholipid bilayers

"I tried to do NMR characterization, but the 1D spectra was so much crowded, so was not able to perform 2D NMR." - one of the reasons to perform 2D NMR is to separate otherwise overlapping resonances.  Also, the use of macroscopically aligned samples (Zhou & Cross Ann Rev Biophys; ) and MAS (Annu Rev Biophys 38:385-403) would help.